Category Archives: Quantum Physics

Equipment in the gravitational wave detector Virgo in Italy.Build Lab / Virgo Cooperation

It keeps you grounded, makes apples fall from trees and directs the cosmic dance between celestial bodies like the earth, sun and moon. However, gravity is perhaps the most unfortunate force in modern physics.

In recent decades, the search for the true nature of gravity has been shown to be the holy grail of physics. Whoever truly understands gravity takes a steady step towards a deeper understanding of the reality around us.

Against this background, three prominent theoretical physicists, including Nobel Prize winner Frank Wilczek, have launched a tantalizing new idea. In the prestigious Physics Journal physical review messages They write that the deeper nature of gravity may be hidden in so-called gravitational waves, the vibrations of space and time that arise, among other things, when heavy objects such as black holes collide in the depths of the universe.

Fundamental forces of nature

First take a step back. Physics distinguishes four fundamental forces of nature. In addition to gravity, this is the electromagnetic force responsible for light and electricity, among other things, the strong nuclear force that ensures that atoms do not disintegrate, and the weak interaction that causes heavier particles to decay into lighter ones. grains.

And while the last three may seem esoteric, its these factorsnot the familiar gravitythat physicists understand best. They are described in the so-called Standard Model of particle physics, the mathematical model that captures all the building blocks of reality and the forces associated with them into a formula that fits in a T-shirt or coffee mug.

In this description, each force has a force-carrying particle a boson, in technical terms that makes the force work in practice. As for the electromagnetic force, this is, for example, a photon, a light particle. This is why many physicists believe that gravity must also contain such a boson. And although no one has seen this particle before, it does indeed have a name: the graviton.

In fact, no one doubts that such a graviton really exists, says theoretical physicist Eric Verlinde (University of Amsterdam). But as in science, youll want to see it for a while. This is where Wilczyk and colleagues new paper comes in. According to them, it should be possible to find the signature of gravitons in gravitational waves.

Noise behind the waves

Back to this standard form. Above all, this uses quantum theory, the set of natural laws that describe the crazy behavior of the particle world. Only: a quantum theory of gravity does not exist yet. One of the main reasons is that the level of energy at which the quantum effect on gravity begins to appear is so ridiculously high that this rarely happens in practice. Except for cosmic collisions that make space and time tremble so that you can measure the gravitational waves generated on Earth.

These physicists I myself sometimes work with first author Molek Baric, with whom I discussed this idea before have a very interesting idea: How many gravitons would be present in such gravitational waves and how would you measure them? says Verlind. , who was not directly involved in the research.

In the quantum world, reality at the most complex level is not smooth, but grainy a vibrant environment completely alien to our senses, where particles flash in and out of reality. According to the new article, these quantum fluctuations should cause a characteristic behavior of the graviton whose signature remains in the measured gravitational waves. It has to appear as a distinct kind of noise, Verlind says. If you measure exactly this noise in several detectors at the same time, you can be sure that it is the signal you are looking for.

According to the authors, the signals should be visible in current Ligo gravitational wave detectors, at two locations in the United States, and Virgo in Italy. However, Verlinde has doubts about whether you can make such a difficult measurement. I think there is only a small chance that something like this will work. I think the chance is greater with the planned new generation of gravitational wave detectors, which can be measured more accurately.

He emphasizes that this does not mean that experimenters should not research. If you are spontaneously trying to find these signals, you develop methods that can make measurements with existing detectors more accurate, he says.

A gravitational wave detector tunnel at the Maiden Tower near Pisa, Italy.Colorbox picture

hard evidence

It is very rare to test theoretical ideas about quantum gravity in experiments. Whereas experiences are the cornerstone of our physical knowledge: only when you measure something in the real world do you know for sure that it exists. Thats why Im part of a consortium with Barrick, among others, thinking about measurable signals from quantum gravity, Verlind says. We believe such signals are detectable. More and more people are taking it seriously now. Finding the expected noise behind gravitational waves is a good first step, Verlind says. This will be the first definitive proof that gravity is in fact quantum mechanical, he says.

If so, it is only a matter of time until physicists can finally complete the formula on their cups and T-shirts with an accurate description of gravity.

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How gravitational waves can lead us to the holy grail of modern physics - Aviation Analysis Wing

September 8, 2021• Physics 14, 122

Researchers demonstrate that they can suppress the formation of defects that appear in superfluid helium-3 when it undergoes a continuous phase transition, allowing them to influence the form of the systems final phase.

When a system that can be described by the 2D Ising model cools, it transitions from having a paramagnetic phase to having a ferromagnetic one via a continuous phase transition. During such a phase transition, magnetic defects can form in the material, creating a nonuniform final ferromagnetic phase. Juho Rysti of Aalto University, Finland, and colleagues now show that they can suppress the formation of these defects in superfluid helium-3when it undergoes a 3D continuous phase transitionby applying a symmetry-breaking bias field to the material [1]. This technique could also be applied to materials undergoing quantum phase transitions, where the appearance of defects can demolish quantum states prepared by adiabatic evolution.

The high-temperature paramagnetic and low-temperature ferromagnetic phases of the 2D Ising model differ by their symmetry: The paramagnetic phase is symmetricthe phase looks the same if the pointing direction of its spins are simultaneously reversedwhile the two ferromagnetic phases of the model are symmetry broken. As a 2D Ising system cools from its paramagnetic phase to a ferromagnetic one, it has to choose which of the two ferromagnetic phases it will transition to, and the evolution of the system slows down near the critical point as the system tries to make this choice.

This critical slowing down causes different parts of the system to move out of thermal equilibrium with each other, something that allows different parts of the system to make independent choices of their magnetization. If the different parts can communicate with each other, the choices can be coordinated, which is more likely for slower cooling rates. Slower cooling rates thus lead to larger domains of one or other of the ferromagnetic phases, with the size of the domains being quantifiable using the Kibble-Zurek-mechanism theory [24]. That said, after the phase transition occurs, the final ferromagnetic phase of the system is almost never uniform but is rather a mosaic of domains of the two ferromagnetic phases (Fig. 1).

The outcome of the phase transition can be made more uniform by applying a magnetic field to the system. For example, if this field points upward as the system cools, the decision will be biased toward the ferromagnetic phase that has spins pointing up. The bias is ineffective for very fast cooling rates because there is not enough time for the field to leave its imprint on the phase of the system. So how slow should the cooling rate be for the bias to be effective in ensuring a uniform ferromagnetic phase? The answer comes again from a generalization of the Kibble-Zurek-mechanism theory, which predicts that the maximal cooling rate scales with the bias strength [5]. The new experiment from Rysti and colleagues shows that when the cooling rate is slow enough, the final phase of the system is an equilibrium ferromagnetic one without any domainsthe first time that has been seen experimentally.

Rysti and his colleagues study a continuous symmetry-breaking phase transition of superfluid helium-3 [1]. Superfluid helium-3 has more complex magnetic behavior than that of the 2D Ising model: Its spins can point in a continuum of directions rather than just up and down, and they can wind into quantized vortices. The nonequilibrium ferromagnetic phase of superfluid helium-3 is a tangle of such vortices, whose density scales with a power of the cooling rate.

In their experiments, the team investigated this scaling behavior by cooling the superfluid using a 3D cryostat and then detecting the orientation of its spins using nuclear magnetic resonance (NMR) coils. In the space between the NMR coils, where the superfluid helium-3 is held, they placed an array of long, thin columns (they call them solid strands), which trap the superfluids vortices.

The experiment shows that when a bias is applied to the systemthe team use both a magnetic field for the bias and also spin-orbit couplingthe power law relating the density of vortices to the cooling rate can break down. Specifically, Rysti and colleagues find that this breakdown happens when the cooling rate falls below a threshold value that is proportional to a power of the bias, with the exponent of the power law being a combination of the universal critical exponents for the transition. Cooling at rates below this threshold value, they find that the density of vortices decays exponentially with cooling time such that the final phase becomes a uniform, equilibrium one.

The team found that the 1-mT bias that they apply is effective only near the phase transitions critical temperature where the system is most susceptible to small perturbations, and even the tiniest of biases can influence the orientation of the spins. They also found that the transition is adiabatic, and as such, they show that cooling with a bias is an efficient way to achieve an adiabatic transition with a finite cooling rate, something that could allow use of the method for adiabatic quantum state preparation in an adiabatic quantum simulator, for example.

The idea of such a simulator is to evolve a system adiabatically from a simple ground state to a more interesting one that cannot be calculated analytically or with a classical computer. If successfully prepared in a quantum simulator, the properties of such a state could simply be measured. Unfortunately, these two ground states are often different enough that to move the system from one to the other requires that the system goes through a quantum phase transition. That means that any adiabatic simulator must be able to evolve a system that is close to its quantum critical point.

This evolution can be described by a quantum generalization of the Kibble-Zurek-mechanism theory, which predicts that, because of a closing of the energy gap of the system at the quantum critical point, excitation of the system is inevitable [6, 7]. It is predicted, however, that in symmetry-breaking transitions these excitations can be suppressed by applying a bias while the system is crossing the quantum critical point [5]. The bias is too weak to affect the properties of the final ground state but is large enough to prevent excitations that would destroy the ground state. The new demonstration by Rysti and colleagues shows that this should be experimentally possible, opening the door to many future experiments on this topic.

Jacek Dziarmaga is a professor at the Jagiellonian University, Poland, where he also obtained his Ph.D. Dziarmaga studies the dynamics of quantum phase transitions. He also develops tensor network algorithms to simulate time evolution of strongly correlated systems in two dimensions.

Researchers demonstrate lighter, smaller optics and vacuum components for cold-atom experiments that they hope could enable the development of portable quantum technologies. Read More

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Controlling the Phase Transition in Superfluid Helium-3 - Physics

The quarks, antiquarks, and gluons of the standard model have a color charge, in addition to all the ... [+] other properties like mass and electric charge that other particles and antiparticles possess. All of these particles, to the best we can tell, are truly point-like, and come in three generations. At higher energies, it is possible that still additional types of particles will exist, but they go beyond the Standard Model's description.

When it comes to the nature of matter in the Universe, the Standard Model describes the known elementary particles perfectly well and without exception, at least so far. There are two classes of fundamental particles:

The fermions come in three generations and are split between the six types of quarks and leptons, while among the bosons, there are no generations, but merely different numbers of them, depending on the nature of the force being mediated. Theres just one boson (the massless photon) for the electromagnetic force, three (the massive W-and-Z bosons) for the weak force, eight (massless gluons), and one (massive) Higgs boson.

All told, the Standard Model provides the framework for all of the known and discovered fundamental particles, but has no way of providing expected values for what masses each particle should possess. In fact, of the fundamental constants needed to describe our Universe, a full 15 of them more than half belong to the rest masses of these particles. And yet, a very simple formula appears to relate many of them to one another, with no explanation as to why. Heres the puzzling story of the Koide formula.

The final results from many different particle accelerator experiments have definitively showed that ... [+] the Z-boson decays to charged leptons about 10% of the time, neutral leptons about 20%, and hadrons (quark-containing particles) about 70% of the time. This is consistent with 3 generations of particles and no other number.

The early 1980s were an extremely successful time for particle physics. The final pieces of the Standard Model had recently been put into place, with the Higgs mechanism, electroweak symmetry breaking, and asymptotic freedom having all been worked out theoretically. On the experimental side, the advent of powerful new colliders had recently revealed the (tau) lepton as well as the charm and bottom quarks, providing empirical evidence for a third generation of particles. With the Main Ring running at Fermilab and the Super Proton Synchrotron collecting the data that would lead to the discovery of the W-and-Z bosons in 1983, the Standard Model was nearing completion.

The quarks are only observable indirectly: as parts of bound states making up mesons (quark-antiquark pairs), baryons (three-quark combinations), and anti-baryons (three-antiquark combinations), requiring a sophisticated theoretical toolkit to extract their rest masses. The leptons, however, are observable directly, and their rest masses were easily reconstructed from the energy and momenta of their decay products. For the three charged leptons, their masses are:

It might appear, on the surface, that theres no relationship between these three masses, but in 1981, physicist Yoshio Koide suggested that there might be one, after all.

A geometrical interpretation of the Koide formula, showing the relative relationship between the ... [+] three particles that obey its particular mathematical relationship. Here, as was its original intent, it's applied to the charged leptons: the electron, muon, and tau particles.

The electron is the lightest charged particle in the Standard Model, and the lightest of all massive particles except for the neutrinos. The muon, its heavier cousin, is identical in terms of electric charge, spin, and numerous other quantum properties, but its mass is ~207 times greater, and its fundamentally unstable, with a mean decay lifetime of ~2.2 microseconds. The tau the third-generation counterpart of the electron and muon is similar but even heavier and shorter lived, with a mass thats about 17 times the muons mass and a mean lifetime of just ~290 femtoseconds, surviving less than one-millionth the amount of time a muon lives for.

No relation, right?

Thats where Koide came in. Perhaps its just a numerical coincidence, but its well known at least, in quantum physics that whenever two particles have identical quantum numbers, theyre going to mix together at some level; youll have a mixed state instead of a pure state. Although this isnt necessarily applicable to the masses of the charged leptons (or any particles at all), its a possibility that might be worth exploring. And its that same mathematical structure that Koide leveraged when he proposed a very simple formula:

which mathematically must lie between and 1. In the case of these charged leptons, it just happens to itself be a simple fraction: , almost exactly.

The Koide formula, as applied to the masses of the charged leptons. Although any three numbers could ... [+] be inserted into the formula, guaranteeing a result between 1/3 and 1, the fact that the result is right in the middle, at 2/3 to the limit of our experimental uncertainties, suggests that there might be something interesting to this relation.

Now, there are many, many relations that one can cook up between various numbers or values that arent actually representative of an underlying relationship, but merely appear as a numerical coincidence. In the early days, people thought the fine-structure constant might be exactly equal to 1/136; a little later, that was revised to 1/137. Today, however, its measured to be 1/137.0359991, and its known to increase in strength at higher energies: up to ~1/128 at electroweak scales. Plenty of suggestive, tantalizing relationships have turned out to be nothing more than coincidences.

And yet, we have precisely measured values for not only the charged leptons, but for each of the quarks as well: the up, down, strange, charm, bottom, and top quarks. The first three are the lightest quarks, the latter three are the heaviest quarks. Using the best data presently available, their masses (shown without uncertainties) are:

Interestingly enough, we can attempt to apply the Koide formula to these six masses in two separate groupings to see what comes out.

The rest masses of the fundamental particles in the Universe determine when and under what ... [+] conditions they can be created, and also describe how they will curve spacetime in General Relativity. The properties of particles, fields, and spacetime are all required to describe the Universe we inhabit.

Remarkably enough, for the up, down, and strange quarks, you get a value of approximately 0.562, which is very close to another simple fraction: 5/9, or 0.55555..., and is allowable within the published uncertainties.

Similarly, we can do a comparable analysis for the charm, bottom, and top quarks together as well, yielding a value of 0.669, which is again very close to a simple fraction of 2/3: 0.666666..., with the exact value, again, allowed within the published uncertainties.

And, if we wanted to be extremely bold, we could move over to the bosons, and check out what the relationship is between the only three massive bosons we have:

Applying the same formula to these three masses yields a value of 0.3362, which appears to be consistent with a simple fraction of 1/3: 0.33333..., which once again seems like a remarkable, almost-perfect coincidence, although in this case, the errors are small enough that the exact relationship cannot be saved.

The particles of the standard model, with masses (in MeV) in the upper right. The Fermions make up ... [+] the left three columns; the bosons populate the right two columns. While all particles have a corresponding antiparticle, only the fermions can be matter or antimatter.

Its important to recognize that these values are only for the pole masses, which is the equivalent of rest mass in relativity. In quantum physics, the only measurements you can make are based on interactions between various quanta, and those interactions always occur at a particular energy thats greater than zero. However, by appropriately applying the correct theoretical techniques, you can disentangle what the pole mass is from the inferred mass that your measurements give you. While the measured masses will change or run with increased energy, the zero-energy limit remains the same.

In fact, although the uncertainties in the measured values of neutrino masses has only yielded constraints on their masses, with everything dependent on the yet-unmeasured particulars of how the various neutrino states mix together, there is reason to believe that there exists some sort of hierarchy between the mass states of the three different types of neutrinos: electron, muon, and tau. Its eminently possible, once those masses can be inferred, that they will also yield an interesting and simple value for the Koide formula.

We haven't yet measured the absolute masses of neutrinos, but we can tell the differences between ... [+] the masses from solar and atmospheric neutrino measurements. A mass scale of around ~0.01 eV appears to fit the data best, and four total parameters (for the mixing matrix) are required to understand neutrino properties. The LSND and MiniBooNe results, however, are incompatible with this simple picture, and should be either confirmed or contradicted in the coming months.

There have also been attempts to extend the Koide formula in various ways, including to all six quarks or leptons simultaneously, with varying successes: you can get a simple relationship for the quarks, but not for the leptons. Others have tried to tease out deeper mathematical relationships that could underpin the rest masses of the fundamental particles, but at this point, these relationships were only knowable after-the-fact, and could not have been used to accurately predict any unknown masses at any point in time.

However, these patterns most definitely persist across applications, from the charged leptons to the light quarks to the heavy quarks to, quite possibly, the massive bosons and the neutrinos as well. It leads to a remarkable question whose answer is not yet known: is the Koide formula something of great importance, and does it provide a hint of some novel structure that might underlie some property of nature that the Standard Model cannot explain? Or, alternatively, is it simply a combination of numerical coincidence (or worse, a near-coincidence) and the human penchant for seeing patterns, even where none exist?

The particles and forces of the Standard Model. Dark matter isn't proven to interact through any of ... [+] the "standard" forces except gravitationally, and is one of many mysteries that the Standard Model cannot account for, along with the matter-antimatter asymmetry, dark energy, and the values of the fundamental constants.

This latter option should be seriously taken into account before we over-invest in this idea. The fine-structure constant is just one example of a numerical relationship that looks promising when you look at it coarsely, but falls apart when you look at things in greater detail. Early attempts at using quark mixing properties to predict the masses of the top quark gave an initial estimate of ~14 GeV/c2 as the mass, whereas its actual mass turned out to be more than 12 times as large as that value.

A little over a decade ago, an attempt was made to use asymptotically safe gravity to predict the mass of the Higgs boson, a few years before it was actually discovered at the Large Hadron Collider. The prediction was astonishingly precise: a mass of ~126 GeV/c2, with an uncertainty of just ~1-2 GeV/c2 in that energy. When the actual discovery was announced, with a value of ~125 GeV/c2, it seemed to vindicate the calculation, but there was a catch: in the intervening time, a number of parameters in the Standard Model were better measured, and that asymptotically safe calculation instead now yielded a value closer to 129-130 GeV/c2. Despite the fact that the original prediction wound up being borne out by experiment, the reasoning behind it no longer holds up.

The first robust, 5-sigma detection of the Higgs boson was announced a few years ago by both the CMS ... [+] and ATLAS collaborations. But the Higgs boson doesn't make a single 'spike' in the data, but rather a spread-out bump, due to its inherent uncertainty in mass. Its mean mass value of 125 GeV/c^2 is a puzzle for theoretical physics, but experimentalists need not worry: it exists, we can create it, and now we can measure and study its properties as well.

This puts us in a particularly precarious position. We have a formula simple in structure that appears to work anywhere from marginally well to extremely well in providing a relationship between a certain fundamental property of matter, rest mass, that cannot be predicted by any theoretical means known today. In many ways, weve reached the limit of the Standard Model of particle physics, as every meaningful prediction that can be extracted from the theory concerning observable quantities has already been teased out.

And yet, the mysterious nature of mass exhibits these approximate relationships. Is there some fundamental reason why the fermions in our Universe come in exactly three copies? Is there a reason why the bosons dont? Is there a reason why the heavy quarks and the charged leptons give the same constant of 2/3 for the Koide formula, but the light quarks are closer to 5/9 and the massive bosons are closer to (but inconsistent with exactly) a value of 1/3? And just what, precisely, are the fundamental masses of the neutrinos, and what sort of hierarchy do they display?

A logarithmic scale showing the masses of the Standard Model's fermions: the quarks and leptons. ... [+] Note the tininess of the neutrino masses. With the latest KATRIN results, the electron neutrino is less than 1 eV in mass, while from data from the early Universe, the sum of all three neutrino masses can be no greater than 0.17 eV. These are our best upper limits for neutrino mass.

By taking the sum of any three numbers, while simultaneously dividing them by the square of the sum of each of their square roots, youll always get a number between 1/3 and 1, without exception. When all three numbers are equal, you get 1/3; if one number is much, much greater than the other two, you get 1. In the Standard Model, we have precisely three generations of fermions. So why is it, then, for both the charged leptons and the three heaviest quarks, that we get a value precisely between those two: of 2/3, while the light quarks give 5/9 and the massive bosons give us a value just a tiny bit larger than 1/3?

At this point, we have no idea. It could all be a simple numerical coincidence, with no rhyme or reason beyond the fact that these values only approximately match the implied correlation. Or, just maybe, its a 40-year-old hint of what might underpin or even take us beyond the Standard Model: a possible mass relation between fundamental particles that the Standard Model itself offers no explanation for. One of the greatest mysteries in physics is why particles have the properties they do. If the Koide formula turns out to be somehow connected to the property of rest mass, we just might have seen an impeccable hint to guide us down the unknown road that lies before us.

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Could This 40 Year Old Formula Be The Key To Going Beyond The Standard Model? - Forbes

As the pandemic ebbed and flowed this summer, we watched the spectacle of billionaires racing to the edge of space. Shortly after reaching an altitude of 53 miles in his rocket plane, Richard Branson heralded the dawn of a new space age, while Jeff Bezoswho flew more than 10 miles higher nine days latersaid he wanted to build a road to space so our kids, and their kids, can build the future. While Mr. Branson dreams of an orbiting hotel, Mr. Bezos of a base on the moon and Elon Musk a colony on Mars, the physicist Paul Davies explores a far wider canvas in his introduction to cosmology, Whats Eating the Universe? This scientific detective story, Mr. Davies tells us, travels from the very edge of time itself, through our own epoch, into the infinite future and weaves together the vastness of space with the innermost recesses of subatomic matter.

Mr. Davies starts with the astonishing discoveries of the 20th century, discoveries now so well established that despite their extraordinary nature they are steadily making the transition into common sense. The universe is 13.8 billion years old, a vast, expanding menagerie of stars complete with exotic beasts such as quasars, supernovas and black holes. In its early history, the universe was hot and densea fact that can be read in the faint remnants that fill the skies. This cosmic microwave background, which was first mapped by the Cosmic Background Explorer satellite in 1990, shows traces of the subtle variations that seeded galaxies, stars and planets. As the missions lead scientist, George Smoot, declared: It was like looking into the face of God.

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Whats Eating the Universe? Review: A Pocket Guide to the Cosmos - The Wall Street Journal

Nicholas Dirks is by no means the first academic or administrator to learn from their own history, but it is notable that such a senior figure has become the latest.

In his recent article for Times Higher Education, Dirks proffers a goal of disciplinary unification as if nothing had transpired since physical chemist and novelist C. P. Snows anachronistic The Two Cultures and the Scientific Revolution of 1959. Dirks a historian and former chancellor of the University of California, Berkeley ignores numerous inter- and cross-disciplinary collaborations across the arts, humanities, social sciences and natural sciences.

Not that these collaborations have always been celebrated. For decades, regardless of qualifications or research foundations, academics have spoken out loudly for but also against one notion or another of interdisciplinarity. The specific form of interdisciplinarity (or transdisciplinarity, multidisciplinarity and so on) is seldom defined or understood critically, in its historical context, and proponents rarely address each other. But these strong statements revolve around a common trope: the centrality of science as a model either to avoid or, more often, to emulate or imitate.

Science has a long and contradictory allure to humanists and social scientists and a chequered legacy. Following science has an intellectual appeal, but the urge to do so also stems from inaccurate, stereotypical or outdated ideas about sciences status, recognition and funding.

On the one hand, certain models of science contributed to successful developments in many subjects, including social science history, historical demography, new political history and economic history, analytical bibliography, digital humanities, reader-response theories, and much more.

On the other hand, science can be a false and misleading goal/god. This is particularly true when academics imitate an image of science uncritically and outside its historical and intellectual context. Consider these examples.

First is the persisting confusion of interdisciplinarity as rhetoric and metaphor, as opposed to conceptualisation, methodology and analytical practice. For instance, one of the long-standing leaders of the Association for Interdisciplinary Studies, Julie Thompson Klein, conflates interdisciplinarity with a whole roster of related but distinct concepts within the span of several pages in one article in the associations in-house journal. These include integration, transdisciplinary, multidisciplinary, transcendent interdisciplinary, interaction, intersection, relationality and translation, professionalisation, interprofessionalism, expansion, holistic and multilevelled, problem-solving, policy studies and team science. None of these terms is defined, but it is clear that some relate to concepts while others relate to practice.

A second example is quantum social science, a newly minted enthusiasm replete with summer boot camps. Among its contradictions is its misunderstanding of both the historical origins of modern social science at the turn of the 20thcentury and the meaning of the term quantum in the context of the transformative quantum revolution and the shifting subsequent status of quantum physics in that discipline.

So often in the history of the humanities and social sciences, envy of the hard sciences exerts a superficial appeal to academics who suffer from an inferiority complex. This cultural phenomenon is also evident in my own field of literacy studies, with its proliferation of new literacies, such as blogging or podcasting. There, too, science is called into play in a number of the exaggerated claims of the uniqueness and power of each proclaimed new literacy.

Quantum social science, meanwhile, finds a rival in neuroscientific literary criticism. This is another metaphorical not theoretical or analytic misapplication from the sciences. As Deborah G. Rogers wrote last month in a review of Angus Fletchers new book on the topic, When science wags literary criticism, the results are unfortunate...literature becomes a form of psychotherapy that releases oxytocin and cortisol. Reading stimulates neurotransmitters... unfortunately, most of these neurological claims are unsubstantiated and unsupported.

To the contrary, Rogers advocates sound interdisciplinary research and interpretation, alongside knowledgeable interchanges between the humanities and the sciences. She emphasises relevant scholarly research and literary criticism, including cognitive theory-of-mind approaches and reader-response/reception theory.

We exist at a moment of suspended animation. Despite at least two generations of ground-breaking interdisciplinarity that draws on the sciences when relevant, scholars in the humanities and social sciences continue to succumb to the temptation of imitating reductionist and/or outdated conceptions of science without regard to their exemplars current status.

This is faux interdisciplinarity. These professors do not do investigate the basics of their subject and alternative approaches to it. Crooked paths advance without signage or road maps, as if the past half century were absent or if their advocates could not visualise or locate the history.

As for the non-debate over interdisciplinarity versus disciplinarity, the compelling question for our own times is how best they can cooperate and collaborate. This differs in fundamental ways from the much earlier two cultures debates, from which scholars must finally move on.

Harvey J. Graff is professor emeritus of English and history at Ohio State University. He is the author of many books on social history, including Undisciplining Knowledge: Interdisciplinarity in the Twentieth Century (Johns Hopkins University Press, 2015).

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Interdisciplinarity is not about the humanities aping the sciences - Times Higher Education (THE)

Launch of The Eindhoven Hendrik Casimir Institute (EHCI) at the Opening Academic Year Event at Eindhoven University of Technology. Photo:Eindhoven University of Technology

Eindhoven University of Technology (TU/e)kickedoff its new research institute on quantum and photonics:the Eindhoven Hendrik Casimir Institute. Thisinstitute was opened byRobbertDijkgraaf, director of the Institute of Advanced Study in Princeton, andGerda Casimir, daughter of Hendrik Casimir.High-techcompany ASML, one of the key partners of TU/e, gave the new institute a set of high-techmachinerydonations worth 3.5M eurosin orderto congratulate the universityonits 65thanniversary.

Eindhoven Hendrik Casimir InstituteWith the exponential growth of our information society, the end of traditional scaling in communications and computingcomeintosight. To continue the trend in computational power and energy-efficient communication, emerging photonics and quantum technologies arekeyavenues to beexplored.Both technologies arealreadyworld-class in Eindhoven,asillustrated by recent multimillion-eurofunds.The Eindhoven Hendrik Casimir Institute (EHCI) willsmartly entanglethe twotechnology fieldsto create synergy: the superfast light-driven communication technology of photonics and the mind-blowing calculation magic of quantum technology.

Hendrik CasimirDutch physicist Hendrik Casimir (1909-2000)ismost famous for his work on superconductivity and quantum physics, most notably the Casimir effect. He also was ahigh-techindustry leader for decadesasthedirector of therenownedPhilips Physics Laboratory.He definedprinciplesfor research management that are still very muchapplicabletoday.

Donations from ASMLASML,the world's leading supplierofthe semiconductor industry,had a great surprise for TU/e, which celebrated its 65thopening of the academic year today. The companygave the university a set of high-technanotechnologymachinesand servicesforthe new institute and forthestudent labs, with a total value of 3.5M euros.

"We are extremely grateful to ASML for these wonderfulpresents,"commentedTU/e President Robert-Jan Smits.These donations underline TU/e's particularly good relationship with ASML and withindustryin theBrainportEindhovenregion."

"We hope that this equipmentwill enable researchers and students at TU/e to push the boundaries of knowledge,achieve scientific breakthroughsand therebycontributeto a better future. Because that is the power of technology. And we hope thatstudents atTU/e will gain even more high-tech knowledge," says Frank Schuurmans, Vice-President Research at ASML,who handed over the gifts symbolicallywith an ICproductionwafer.

More information about the Eindhoven Hendrik CasimirInstitute:https://www.tue.nl/en/news-and-events/news-overview/06-09-2021-new-institute-will-entangle-next-generation-photonics-and-quantum-technologies/

More information about the Opening of the Academic Year of TU/e:https://www.tue.nl/en/news-and-events/news-overview/02-09-2021-science-and-industry-figureheads-take-center-stage-at-opening-of-65th-academic-year/

More information about the gifts of ASML to TU/e:https://www.tue.nl/en/news-and-events/news-overview/asml-makes-generous-donations-to-the-65-year-old-tue/

This article was first published on September 6 by TU/e.

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TU/e launches the Eindhoven Hendrik Casimir Institute on Quantum and Photonics - Science Business

Like Sebald, Labatut sees historys patterns as cyclical rather than linear, crossing similar terrain again and again as they wend their way toward disaster. But he is focussed equally on the question of what happens once we become aware of the enormity of the destruction that humankind is capable of inflicting on the worldand whether our brains are wired to cope with that fatal understanding. After such knowledge, what forgiveness?

For Schwarzschild, the key to the universe lay in astronomy. Born in Germany in the late nineteenth century, he built his own telescope as a child and published his first astronomy paper at sixteen. By twenty-eight, he was the director of the observatory at the University of Gttingen. Like many German Jews, he was deeply patriotic: as Labatut tells it, he believed that Germany could someday rise to the height of ancient Greece in its ability to civilize the world, but first its scholarship in science must equal its achievements in philosophy and art. Only a vision of the whole, like that of a saint, a madman or a mystic, will permit us to decipher the true organizing principles of the universe, Labatut quotes him as writing.

When, late in 1915, Einstein published his theory of general relativity, Schwarzschild was serving in the German Army. Within a month, he had solved Einsteins field equations, and what he found profoundly destabilized his own conception of the organization of space. According to Schwarzschilds calculations, when a star is in the throes of collapse, it compresses, its density increasing until the force of gravity distorts space and time around it. The result, in Labatuts words, is an inescapable abyss permanently cut off from the rest of the universe, at the center of which lies the singularity, where the notions of space and time themselves became meaningless.

By now, the concept of the black hole is familiar. But at the time it seemed a harbinger of chaos and destruction. Inside the void his metrics predicted, the fundamental parameters of the universe switched properties: space flowed like time, time stretched out like space, Labatut writes. If a hypothetical traveler were capable of surviving a journey through this rarefied zone, he would receive light and information from the future, which would allow him to see events that had not yet occurred. A person who stood within the singularityimpossible, since gravity would tear him to bitscould see both the entire future evolution of the universe at an inconceivable pace and the past frozen in a single instant. The singularity itself is surrounded by a barrier marking a point of no return, beyond which nothing can cross without getting sucked in; the dimension of this boundary is now known as the Schwarzschild radius.

Up to here, this chronicle of Schwarzschilds life is largely verifiable. Now Labatut takes matters a step further. Not only was Schwarzschild terrified by his discovery, in Labatuts telling, but he became obsessed with it. He supposedly confessed to a colleague who visited him in the military hospitalhe was suffering from pemphigus, a painful and disfiguring autoimmune disease primarily affecting the skinthat the true horror of the singularity was that it was a blind spot in the universe, fundamentally unknowable. If the physical world was capable of generating such a monstrosity, what about the human psyche? Could a sufficient concentration of human willmillions of people exploited for a single end with their minds compressed into the same psychic spaceunleash something comparable to the singularity? In Schwarzschilds mind, such a thing was taking place at that very moment in Germany. He had visions of a black sun dawning over the horizon, capable of engulfing the entire world. By the time people became aware of it, it would be too late:

The singularity sent forth no warnings. The point of no returnthe limit past which one fell prey to its unforgiving pullhad no sign or demarcation.... If such was the nature of that threshold, Schwarzschild asked, his eyes shot through with blood, how would we know if we had already crossed it?

The gravitational pull of fiction in this book works in a similar fashion. The dividing line between reality and imagination is not marked; it is only after several paragraphs or pages that we realize we have crossed it. We know, for instance, that Heisenberg did indeed travel to Helgoland in 1925, seeking relief from his allergy to pollen (the microscopic particles that were torturing him), and there reached his understanding of the behavior of elementary particles, discovering a way to describe the location of an electron and its interaction with other particles. But did the frenzy of his intellectual energy combine with fever to generate nightmares in which the Sufi mystic Hafez appeared in his bedroom, offered him a wineglass filled with blood, and masturbated in front of him before receiving oral sex from Goethe? We assume not, but the boundary is obscured by the gothic fervor of Labatuts narration, in which even mundane details are relayed with heavy melodrama: Heisenbergs allergies transform him into a monster, his lips swollen like a rotten peach with the skin ready to come off.

Likewise, we know that the physicist Erwin Schrdinger spent time in a sanatorium recovering from tuberculosis, but Labatut seems to have invented a fantasy romance for him there, involving the teen-age daughter of the doctor who runs the institution. Herself a TB patient, she distracts herself from her illness by experimenting with a type of aphid that gestates while still in utero, resulting in three generations nestled one inside the other. She separates them and exposes them to a pesticide thatsure enoughstained the glass such a striking shade of blue that it seemed as though she were looking at the primordial colour of the sky. Like those aphids, the stories in this book nest inside one another, their points of contact with reality almost impossible to fully determine. As the layers of patterns and affinities accumulated, I realized that I was no longer compulsively Googling, instead allowing the stories to flow.

There is liberation in the vision of fictions capabilities that emerges herethe sheer cunning with which Labatut embellishes and augments reality, as well as the profound pathos he finds in the stories of these men. But there is also something questionable, evennightmarish, about it. If fiction and fact are indistinguishable in any meaningful way, how are we to find language for those things we know to be true? In the era of fake news, more and more people feel entitled to make our own reality, as Karl Rove put it. In the current American political climate, even scientific factthe very material with which Labatut spins his webis subject to grossly counter-rational denial. Is it responsible for a fiction writer, or a writer of history, to pay so little attention to the line between the two?

Labatut seems to gesture toward a justification for his mode of narrative in his long section on Heisenberg and Schrdinger, which gives the book itsEnglish title. (In Spanish, it is called Un Verdor Terrible, which might be translated as something like A Terrible Greenness, a reference to another nightmarish vision, this one supposedly experienced by Haber, of plants taking over the world.) Heisenberg argued that quantum objects have no intrinsic properties; an electron does not occupy a fixed location until it is measured. In Labatuts telling, Heisenberg, following this idea to its limits, reflects:

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Benjamn Labatuts When We Cease to Understand the World, Reviewed - The New Yorker

In 1905, Albert Einstein showed in his Special Theory of Relativity that space is intimately connected to time via the cosmic speed limit of light and so, strictly speaking, we live in a Universe with four dimensions of space-time. For everyday purposes however, we think of the Universe in three dimensions of space (north-south, east-west, up-down) and one dimension of time (past-future). In that case, a fifth dimension would be an extra dimension of space.

Such a dimension was proposed independently by physicists Oskar Klein and Theodor Kaluza in the 1920s. They were inspired by Einsteins theory of gravity, which showed that mass warped four-dimensional space-time.

Since were unable to perceive these four dimensions, we attribute motion in the presence of a massive body, such as a planet, not to this curvature but to a force of gravity. Could the other force known at the time (the electromagnetic force) be explained by the curvature of an extra dimension of space?

Kaluza and Klein found it could. But since the electromagnetic force was 1,040 times stronger than gravity, the curvature of the extra dimension had to be so great that it was rolled up much smaller than an atom and would be impossible to notice. When a particle such as an electron travelled through space, invisible to us, it would be going round and round the fifth dimension, like a hamster in a wheel.

Kaluza and Kleins five-dimensional theory was dealt a serious blow by the discovery of two more fundamental forces that operated in the realm of the atomic nucleus: the strong and weak nuclear forces.

But the idea that extra dimensions explain forces was revived half a century later by proponents of string theory, which views the fundamental building blocks of the Universe not as particles, but tiny strings of mass-energy. To mimic all four forces, the strings vibrate in 10-dimensional space-time, with six space dimensions rolled up far smaller than an atom.

String theory gave rise to the idea that our Universe might be a three-dimensional island, or brane, floating in 10-dimensional space-time. This raised the intriguing possibility of explaining why gravity is so extraordinarily weak compared with the other three fundamental forces. While the forces are pinned to the brane, goes the idea, gravity leaks out into the six extra space dimensions, enormously diluting its strength on the brane.

There is a way to have a bigger fifth dimension, which is curved in such a way that we dont see it, and this was suggested by the physicists Lisa Randall and Raman Sundrum in 1999. An extra space dimension might even explain one of the great cosmic mysteries: the identity of dark matter, the invisible stuff that appears to outweigh the visible stars and galaxies by a factor of six.

In 2021, a group of physicists from Johannes Gutenberg University in Mainz, Germany, proposed that the gravity of hitherto unknown particles propagating in a hidden fifth dimension could manifest itself in our four-dimensional Universe as the extra gravity we currently attribute to dark matter.

Though an exciting possibility, its worth pointing out that theres no shortage of possible candidates for dark matter, including subatomic particles known as axions, black holes and reverse-time matter from the future!

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Our Universe may have a fifth dimension that would change everything we know about physics - BBC Science Focus Magazine

Your correspondence on quantum mechanics (Editorial, 30 August; Letters, 3 September) reminded me of a conversation that I had 50 years ago with a German biologist. He told me that as a teenager he had wanted to be a theoretical physicist and went to a lecture by Wolfgang Pauli on the latters exclusion principle. Seeking out Pauli at the end, he said: That was wonderful, I could see exactly what you meant. Paulis reply: If you could see it, you didnt get it. I gathered that was why he chose biology.Prof John GallowayCroxley Green, Hertfordshire

Richard Walker (Letters, 3 September) is right about the brilliant Crossroads TV theme. Ive always felt that some programmes were more popular than they deserved to be purely because of their theme tune. An obvious candidate was the 1970s detective series Van der Valk, whose excellent theme tune, Eye Level, seemed to raise it above the average.Dougie MitchellEdinburgh

Re weather forecasts (Letters, 2 September), I was reminded of the words of a visiting American acquaintance in the 1980s. Im not sure why you Brits bother with weather forecasts, he said. There are only three states of weather in the UK: its just stopped raining, its raining, or its just about to rain.Ray WoodhamsBarnsley, South Yorkshire

Simon Jenkins says the Afghan war cost Britain 37bn (Biden isnt the first president to promise never to wage another war of intervention, 3 September). That is the same amount that Boris Johnson allocated to NHS test and trace (provided by private companies). Astonishing. Jeanne WarrenOxford

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Just when you think youve got physics - The Guardian

Your editorial on quantum physics (30 August) starts with a quote from Richard Feynman nobody understands quantum mechanics and then says that is no longer true. One of us (Norman Dombey) was taught quantum theory by Feynman at Caltech; the other (John Charap) was taught by Paul Dirac at Cambridge. Quantum theory was devised by several physicists including Dirac, Erwin Schrdinger and Werner Heisenberg in the 1920s and 1930s, and Dirac made their work relativistic.

It is absurd to say that quantum mechanics is now understood whereas it was not 50 years ago. There have of course been advances in our understanding of quantum phenomena, but the conceptual framework of quantum physics remains as it was. The examples you give of nuclear plants, medical scans and lasers involve straightforward applications of quantum mechanics that were understood 50 years ago.

The major advance in the understanding of quantum physics in this period is a theorem of John Bell from Cern, which states that quantum physics cannot be local that is to say that it permits phenomena to be correlated at arbitrarily large distances from each other. This has now been demonstrated experimentally and leads to what is known as quantum entanglement, which is important in the development of quantum computers. But even these ideas were discussed by Albert Einstein and coworkers in 1935.

The editorial goes on to say that subatomic particles do not travel a path that can be plotted. If that were so, how can protons travel at the Large Hadron Collider at Cern and hit their target so that experiments can be performed?

We agree with Phillip Ball, who wrote in Physics World that quantum mechanics is still, a century after it was conceived, making us scratch our heads. There are many speculative proposals in contention but none have consensus support. John Charap Emeritus professor of theoretical physics, Queen Mary University of London; Norman Dombey Emeritus professor of theoretical physics, University of Sussex

Whoever wrote this editorial does not understand what Richard Feynman meant when he said that nobody really understands quantum mechanics. Being able to make a smartphone, a nuclear weapon or an MRI machine does not require understanding quantum mechanics in the sense he meant it requires the physical chops to set up the equations and the mathematical chops to find or approximate solutions to them. Any competent physicist has been able to do those calculations for at least 50 years. What Feynman meant was that, for quantum mechanics, nobody has the kind of intuitive understanding of what is actually happening in the world that physicists seek to gain. All we can do is shut up and calculate, or get lost in a never-never land of competing but empirically equivalent interpretations.

Perhaps Carlo Rovellis relational interpretation of quantum mechanics provides the intuitive understanding wed like to have, although I rather doubt it, and I dont believe Rovelli claims it does. Perhaps it even makes testable predictions that could distinguish it from other interpretations and thus is science rather than philosophy (I have no objection to philosophy).

It is just as true today as it was when Feynman said it in 1964 that nobody (or almost nobody) really understands quantum mechanics. And now, as then, a competent physicist does not need the kind of understanding Feynman meant to use the theory. Indeed, theres no strong reason to believe that the human mind should be equipped to understand it at all. To quote another famous physicist: this editorial is not even wrong.Tim BradshawNorth Tawton, Devon

While its highly probable that the position of my copy of Helgoland is where I shelved it, I wont know whether its pages are printed or blank until I get round to reading it. However, from Prof Rovellis previous work, I agree the fundamental truth is that its impossible to know everything about the world, including whether this letter will be published and in what world.Harold MozleyYork

Given your editorial on quantum physics, is the strapline now facts are relatively sacred or facts are sacred but relative?Simon TaylorWarwick, Warwickshire

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Quantum of solace: even physicists are still scratching their heads - The Guardian