Daily Archives: April 17, 2021

Physicists have long been unable to crack the mystery of what happened in the moments when a vanishingly small seed ballooned into the universe. Now, one scientist thinks he knows why they can't come up with a physical description of this phenomenon called inflation: The universe won't let us.

Specifically, the scientist describes a new conjecture that states, regarding the young universe, "the observer should be shielded" from directly observing the smallest structures in the cosmos.

In other words, by definition physicists may never be able to build a model of inflation using the usual tools, and they will have to come up with a better way.

Related: From Big Bang to present: Snapshots of our universe through time

But why not? This new conjecture, which is an opinion or thought based on incomplete information, points the finger of blame at a particular feature of inflation models. These models take very, very small fluctuations in spacetime and make them bigger. But we don't have a complete physical theory of those small fluctuations, and so models of inflation that have that feature (which is almost all of them) will never work.

Enter string theory, which could be the key to elucidating the secrets of inflation.

Observations of the large-scale structure of the universe and the leftover light from the Big Bang have revealed that in the very early universe, our cosmos likely experienced a period of incredibly rapid expansion. This remarkable event, known as inflation, drove the universe to become trillions upon trillions of times larger in the tiniest fraction of a second.

In the process of getting huge, inflation also made our cosmos a little bit bumpy. As inflation unfolded, the tiniest random quantum fluctuations fluctuations built into the very fabric of space-time itself got much, much larger, meaning some regions were more densely packed with matter than others. Eventually, those sub-microscopic differences grew to become macroscopic and even bigger, in some cases stretching from one end of the universe to the other. Millions and billions of years later, those tiny differences in density grew to become the seeds of stars, galaxies and the largest structures in the cosmos.

Related: The 12 biggest objects in the universe

Astronomers strongly suspect that something like this inflation story happened in the early moments of the universe, when it was less than a second old; even so, they don't know what triggered inflation, what powered it, how long it lasted or what shut it off. In other words, physicists lack a complete physical description of this momentous event.

Adding to the mix of mysteries is that in most models of inflation, fluctuations at exceedingly tiny scales get inflated to become macroscopic differences. How tiny? Tinier than the Planck length, or roughly 1.6 x 10^minus 35 meters (the number 16 preceded by 34 zeroes and a decimal point). That's the scale where the strength of gravity rivals that of the other fundamental forces of nature. At that scale, we need a unified theory of physics in order to describe reality

We have no such theory.

So we have a problem. Most (if not all) models of inflation require the universe to grow so large that sub-Planckian differences become macroscopic. But we don't understand sub-Planckian physics. So how could we possibly build a theoretical model of inflation if we don't understand the underlying physics?

Maybe the answer is: We can't. Ever. This concept is called the trans-Planckian Censorship Conjecture, or TCC (in this name, "trans-Planckian" means anything reaching below the Planck length).

Robert Brandenberger, a Swiss-Canadian theoretical cosmologist and a professor at McGill University in Montreal, Canada, recently wrote a review of the TCC. According to Brandenberger, "The TCC is a new principle which constrains viable cosmologies." In his view the TCC implies that any observer in our large-scale world can never "see" what happens at the tiny trans-Planckian scale. Even if we had a theory of quantum gravity, the TCC states that anything living in the sub-Planckian regime will never "cross over" into the macroscopic world. As to what the TCC might mean for models of inflation, unfortunately it's not good news.

Most theories of inflation rely on a technique known as "effective field theory." Since we don't have a theory that unifies physics at high energy and small scales (a.k.a. conditions like inflation), physicists try to build lower-energy versions to make progress. But under the TCC, that kind of strategy doesn't work, because when we use it to build models of inflation, the process of inflation happens so rapidly that it "exposes" the sub-Planckian regime to macroscopic observation, Brandenberger said.

Related: What happened before the Big Bang?

In light of this issue, some physicists wonder if we should take a completely different approach to the early universe.

String gas cosmology is a possible approach to modeling the early universe under string theory, which is itself a hopeful candidate for a unified theory of physics that brings classic and quantum physics under the same roof. In the string gas model, the universe never undergoes a period of rapid inflation. Instead, the inflation period is much gentler and slower, and fluctuations below the Planck length never get "exposed" to the macroscopic universe. Physics below the Planck scale never grows up to become observable, and so the TCC is satisfied. However, string gas models don't yet have enough detail to test against the observable evidence of inflation in the universe.

Related: What is the smallest thing in the universe?

The TCC is related to another sticking point between inflation and theories of unified physics like string theory. String theory predicts an enormous number of potential universes, of which our particular cosmos (with its set of forces and particles and the rest of physics) represents only one. It seems as if most (if not all) models of inflation are incompatible with string theory at a basic level. Instead, they belong to what string theorists called the "swampland" the region of possible universes that simply aren't physically realistic.

The TCC could be an expression of the swampland rejection of inflation.

It may still be possible to build a traditional model of inflation that satisfies the TCC (and lives outside string theory's swampland); but if the TCC is true, this severely limits the kinds of models that physicists can build. If inflation manages to proceed for a short enough period of time (imagine blowing up a balloon slowly and stopping before it pops), while still planting the seeds that will someday grow up to be massive structures, inflation theory might work.

Right now, the TCC is unproven it's just a conjecture. It lines up with other lines of thinking of string theory, but string theory is itself also unproven (in fact, the theory isn't complete and isn't even able to make predictions yet). But still, ideas like this are useful, because physicists fundamentally don't understand inflation, and anything that can help sharpen that thinking is welcome.

Originally published on Live Science.

See the original post here:

Will we ever know exactly how the universe ballooned into existence? - Livescience.com

Chanda Prescod-Weinstein is an award-winning physicist, feminist, activist and the first Black woman to earn a PhD in the field of theoretical cosmology. Photo: Chanda Prescod-Weinstein

Every community guards a creation story, a theory of cosmic origins. In much of sub-Saharan West Africa, for the past few thousand years, itinerant storytellers known as griots have communicated these and other tales through song. Cosmologists also intone a theory of cosmic origins, known as the Big Bang, albeit through journal articles and math.

Chanda Prescod-Weinstein is a cosmologist who is adept with both equations and the keeper of a deeply human impulse to understand our universe. In her first book, The Disordered Cosmos: A Journey into Dark Matter, Spacetime, & Dreams Deferred, Prescod-Weinstein also admits she is a griot, one who knows the music of the cosmos but sings of earthbound concerns. She is an award-winning physicist, feminist, and activist who is not only, as she says, the first Jewish queer agender Black woman to become a theoretical cosmologist, she is the first Black woman ever to earn a PhD in the subject.

Prescod-Weinsteinis an assistant professor of physics and astronomy, and a core faculty member in the department of womens and gender studies at the University of New Hampshire. She thus enjoys a unique frame of reference from which to appraise science and her fellow scientists. She is an insider whom others nonetheless cast as an outsider, because of her identity, orientation, and the tint of her skin. From the outside, however, she admits a fuller view of her field. She perceives the structures that were invisible to people, and reveals them.

The Disordered Cosmos is equal parts critical analysis, personal essay and popular science. It is an introspective yet revelatory book about the culture of physics and the formative years of a scientific career.

Growing up during the 1990s in East Los Angeles, where at night the dominant lights flashed red and blue, Prescod-Weinstein owned a telescope but rarely saw the stars. She was a born empiricist who decided to become a physicist at the age of 10, after her single mother took her to see the documentary A Brief History of Time. Her mother, the journalist and wage activist Margaret Prescod, continually nourished the young girls passion. She took a teenage Prescod-Weinstein to Joshua Tree National Park, where they spent a night observing the Comet Hyakutake, unblinded by city lights.

After arriving at Harvard University to study physics, Prescod-Weinstein struggled academically, in part because of her own extracurricular advocacy for providing a living wage to campus workers. Yet a classmate tried to help her realise her childhood dream. He offered her a job at a new observatory atop Maunakea in Hawaii, where the view to the heavens was among the most limpid on Earth. There she could earn better than a living wage in the astronomers efforts to gather photons particles of light that will help them tell our cosmological story.

Prescod-Weinstein imagined dedicating herself to pure physics in this idyllic locale, with beaches, amazing tans, and an opportunity to start over. But no physics is pure, no place such an idyll. Astronomers had started building their telescopes on Maunakea during the 1960s against the protests of native Hawaiians, for whom the summit is sacred. Her living wages, she realised, would have underwritten the erasure of another peoples cosmology.

I promised myself that I would make more room in my life for my dreams of being a physicist, she wrote. But not like this. She now supports the native Hawaiians who have vowed to protect their unceded lands against the impending construction of the Thirty Meter Telescope, which might yet become the worlds largest.

Prescod-Weinstein not only narrates her struggle to become a cosmologist, she advocates for all peoples whom physicists have undervalued. She praises the assistants and janitors, mostly people of colour, whose labor permits theorists to ponder the universe daily, because part of science is emptying the garbage. She elevates her elders, such as Elmer Imes and Ibn Sahl, whose contributions others have disregarded because these forebears were not of European descent.

The beauty of mathematics and the majesty of the stars attracted Prescod-Weinstein to cosmology. They sustain her. Yet, she writes: Learning about the mathematics of the universe could never be an escape from the earthly phenomena of racism and sexism.

So, Prescod-Weinstein unveils the majesty that oppression obscures. In the opening quarter of her book, she hurries readers through a tour of physics, rushing past Bose-Einstein condensates, axions, and inflatons to arrive at her own research into dark matter. Its a brilliant sprint, and the prize for finishers is some of her finest writing about race and science.

Prescod-Weinstein includes a thunderous essay about scientists historical neglect of the biophysics of melanin and the repercussions today. Later, there is a chapter that she did not want to write about an episode from her life that she did not want to share. She had no choice, she explained, because Rape is part of science and a book that tells the truth about science would be a lie if I were to leave out this chapter. Her account is so fierce and switches registers so regularly, as if gliding between chorus and verse, that the writing becomes incantatory. She saps the events power to define her, transmuting pain into affecting prose.

Prescod-Weinstein is attuned to the language of physicists, especially the biases it elides, as when her colleagues speak of coloured physics, more commonly known as quantum chromodynamics, which she describes as a theory that uses colour as an analogy for physical properties that have nothing to do with colour. She is adept at then rephrasing physics to redress those biases. Systemic racism is compared to weak gravitational lensing, the subtle distortion of light owing to the curvature space and time around distant galaxies. Cyclical time is intuitive to a person who menstruates. The wave-particle duality reveals the queer, nonbinary nature of quantum mechanics. Dark matter is not actually dark: Its transparent more like a piece of glass than a chalkboard. Not only is the name antithetical to the science, some physicists have compared such invisible matter, crudely, to Black people.

Also read: Astronomers May Not Like It but Astronomy and Colonialism Have a Shared History

Studying the physical world requires confronting the social world, Prescod-Weinstein writes. It means changing institutionalised science, so that our presence is natural and our cultures are respected. It also means confronting the privileged stories of science.

The demographics of physicists still reflect the iniquities of the past. And physics remains diminished because of its biases. Whenever we exclude whole peoples, we not only disallow their questions we disavow their knowledge. The field squanders other cultures perceptions of time. And as Prescod-Weinstein notes, physicists may even misinterpret the wave-particle duality and confuse the rotating identities of neutrinos because they are too oriented toward binaries.

The Disordered Cosmos is not perfect. There are phrases that Prescod-Weinstein might have heated longer or squeezed harder until they crystallised. There are intervals when the pressure of having to cite so many ideas make matters too dense. But these are quibbles. Besides, the defects of an otherwise ideal crystal can render it more colourful and electric.

Prescod-Weinstein aspires to loftier matters. The books frontispiece is a sketch of two women who remind her that even in the worst conditions, Black women have looked up at the night sky and wondered. These women were slaves, who not only navigated the stars to freedom but also wondered at that black expanse. They are as much my intellectual ancestors as Isaac Newton is.

Prescod-Weinsteins most vital work, in the end, is the emancipation of Black and brown children who still cannot see their futures in the stars. She distills this labor in a series of questions: What are the conditions we need so that a 13-year-old Black kid and their single mom can go look at a dark night sky, away from artificial lights, and know what they are seeing? What health care structures, what food and housing security are needed?

Prescod-Weinstein teaches that all humans are made of luminous matter. And she knows just how radiant people can be, despite the obstacles in their way. She understands, intimately, that Black people hunger for a connection to scientific thought and will overcome the barriers placed in front of them in order to learn more.

Joshua Roebke is finishing a book on the social and cultural history of particle physics, titled The Invisible World. He won a Whiting Foundation Creative Nonfiction Grant and teaches literature and writing at the University of Texas at Austin.

This article was originally published on Undark. Read the original article.

Read more from the original source:

'The Disordered Cosmos', A Contemplation of the Exclusionary Culture of Physics - The Wire Science

Albert Einstein is the genius we all know and love. He was a German theoretical physicist. He is known as one of the greatest physicists of all time and for developing the theory of relativity.

He also made important contributions to the development of the theory of quantum mechanics. He received the 1921 Nobel Prize in Physics for his services to theoretical physics and especially for his discovery of the law of photoelectric effect which was a pivotal step in the development of quantum theory.

April 18 is the death anniversary of this great man.

How did Albert Einstein die?

World-renowned physicist Albert Einstein passed away in Princeton Hospital in New Jersey on 18 April, 1955. The cause of his death was the rupture of an aneurysm, which had already been reinforced by surgery in 1948.

He refused to undergo further surgery saying, "I want to go when I want. It is tasteless to prolong life artificially. I have done my share, it is time to go. I will do it elegantly." He kept working almost to the very end, leaving the Generalized Theory of Gravitation unsolved.

He was 76 years old at the time of his death. However, his last words will forever remain unknown as they were uttered in his native German. On his deathbed, he muttered a few last words in that language and the only witness was his nurse but, unfortunately, she didn't speak the language.

Famous Quotes of Albert Einstein:

1. Imagination is more important than knowledge.

2. If you can't explain it simply, you don't understand it well enough.

3. Life is like riding a bicycle. To keep your balance you must keep moving.

4. Imagination is everything. It is the preview of life's coming attractions.

5. No problem can be solved from the same level of consciousness that created it.

Read the original:

Albert Einstein Death Anniversary: How did the greatest physicists of all time die? - Free Press Journal

Author Krista Foss with her new novel, Half Life.

Fehn Foss/Handout

At the Milwaukee high school where she teaches physics, Elin, the protagonist of Krista Fosss new novel, Half Life (M&S), often uses unorthodox methods to explain principles like nuclear fission and chain reactions to her students. Far more complex, and at times less explicable, however, are the reactions occurring in Elins own family in the wake of the sudden death of her father, a revered Danish-born furniture designer.

Foss has twice been a finalist for the Journey Prize for her short fiction. Her previous novel, Smoke River (2014), won the Hamilton Literary Award. She lives in Hamilton.

This novel is a notable departure from your previous one, at least in terms of subject matter. How did it come to you?

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I spent four years writing something else an entirely different book that I would have kept expanding and retooling had not my daughter, whose judgment I trust implicitly, found the courage to tell me it wasnt working and wasnt likely to either. As far as moments go, that was a devastating one. And not an easy message for her to deliver. At a gut level, I knew she was right as she was when she pointed to this other story, sniffing around the edges of the unsalvageable manuscript, suggesting I dig into that. It scared the bejeezus out of me. But my other option was to get depressed over having noodled away for four years with nothing to show for it.

So, Half Life was written in a swoon of fear, with equal parts humiliation and humility, but also a lot of love for mothers, daughters, the complexities of family. And those really brave moments when someone has to say something thats both true and devastating.

The grace note was the first draft came out quickly; it seemed to have been there all along. And because Half Life is a close character study, told with a singular voice, it feels wholly different from my first novel, which had 12 points of view. I got to stretch myself in a new way.

The specificity of its setting and characters is one of the most interesting things about Half Life. Why did you set it in Milwaukee?

Milwaukee was the whim that became the premeditated choice. I wanted Elin to live in a mid-sized city, that for her feels midway to somewhere else, namely the bigger cities her more accomplished siblings left Milwaukee for.

I also mistakenly thought Milwaukee had a large Danish-American population, so when I landed there during a January snowstorm, I thought Id be tripping over Scandinavians. But the more I discovered about Milwaukee the more it felt kindred to me, an inveterate Hamiltonian: its ugliness and its beauty and other troubling contradictions. Its the largest city in the U.S. to have elected socialist mayors. Yet, it remains racially segregated, divided by money, full of industrial pride, yet abandoned by many industries.

And then I discovered the curious, not-so-well-known role Milwaukee played in The Manhattan Project, and it worked so perfectly with the novel, I started to believe Id chosen the city on purpose, rather than acting on a gut feeling that led to productive serendipities.

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The patriarch in the novel, Tig, is a famous Danish mid-century furniture designer. How much did you know about such things before you began writing?

My childhood home was originally filled with Scandinavian mid-century modern furniture, but it didnt hold up under assault from me and my siblings: five very large, unruly children born in quick succession. It was replaced with rough-hewn pine benches and homemade durable sofas. Still, I never shook the impression of the earlier furnitures angles and curves, the low-lustre teak, the dark-striped boucle, all of it registering as birdlike, weird and beautiful.

So, my knowledge of Danish mid-century modern design begins with an old emotion supplemented by some later book-learning, BBC documentaries and hours spent staring at the offerings of online auction houses. Also, if a chair is unadorned physics it has to hold itself up under the forces of gravity, and then it has to hold you the Danish made it look cool to my eyes.

For much of my life, that was about my working level of physics that, and a disastrous first year of university engineering.

And yet physics and physicists also play a major role in the novel, so Im assuming you had to do a lot of research in that realm as well?

I backed into theoretical physics for this book through recreational reading on whats called the hard problem of consciousness and stumbling on how neurology, philosophy, computer science and physics have all staked out turf in this debate (and turfs inside turfs). Its vociferous, and sometimes veers toward the polemical. And in going down that rabbit hole, I read more about theoretical physics than I expected to. At the simplest level, I became intrigued by how much we do in this world that breezes over underlying paradox: science works even when its practitioners dont fully understand or agree on how or why. The consciousness question didnt show up in my book, but the physics did.

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Eventually, research has a showdown with hubris. I couldnt become an expert on subjects others have dedicated their lives to mastering. In an early draft, my main character had long conversations with Niels Bohr on the epistemological questions arising from quantum mechanics. Thats not great fiction or at least not the way I wrote it. And it taught me another lesson: resist using most of your research.

Ultimately, I needed to understand as much of the physics that interested my character and that she would use in the context of her story arc. That allowed me to approach the subject with more wonder. What does she contemplate walking through busy halls holding a full cup of coffee? How does Schrodingers cat show up in her dreams? Who are the physicists she wishes she knew?

So did you emerge from it with a favourite physicist, or theorem?

Physicists fascinate me how often messy lives produce brilliant, elegant science. But it was the female physicists in the period straddling the foundations of quantum mechanics and the beginnings of nuclear physics who left the deepest impressions, because other than Marie Curie and her daughter, they were largely shut out of recognition and rewards a reality thats only recently shifting with the 2018 and 2020 Nobel Prizes in Physics. Among them was Lise Meitner, exiled from her beloved Berlin, tromping off in the snow with her nephew to sit down in a Swedish forest and scribble calculations on the back of stationery that confirmed nuclear fission. For the man whod betray her. She had that trifecta of emotional complexity, deep humanity and utter brilliance.

People like to say things dont matter, and yet objects in this novel have a weight and a power. Can you talk about that?

Things matter in this novel insofar as they are matter. Which is Elins central dilemma. Her memory is analogous to quantum physics: she cant produce visible tangible evidence. It is dogged by uncertainty. And yet, it is an underlying reality.

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The other reality is material, the realm of classical physics dealing with the insults of time to her body and home, seeing her daughter bruised, a branch falling in her path. Even the bombs that fell in the past have macroscopic footprints.

So, the objects in the book a beautiful chair or dining set, a collection of smoky Danish glass mirror the dilemma. They have their own classical reality, the substances they are made of and their tactile aesthetics. But these are overlaid with strata of narrative: who designed them, how they are made and where the wear and tear came from. And finally, that invisible encoding of memory: the laughter, meals, song, comfort and wounds they hold. The secrets.

The paradoxes we cant see joy co-existing with pain along those we can aesthetic delight simultaneous with ugliness, with stain can all be the reality of something as utilitarian, yet intimate, as a chair or a table or a drinking glass.

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Continued here:

Half Life traces family complexities for a Milwaukee physics teacher - The Globe and Mail

Scott Aaronson is therecipient of the 2020 ACM Prize in Computing for his "groundbreaking contributions to quantum computing." Aaronson, who is Professor of Computer Science at the University of Texas, Austin, has also made fundamental contributions to classical complexity theory.

The award, which was established in 2007 to recognize "early to mid-career fundamental innovative contributions in computing" carries a prize of $250,000, with its financial support provided by Infosys Ltd.

In today's announcement,Pravin Rao, COO of Infosys states:

Infosys is proud to fund the ACM Prize in Computing and we congratulate Scott Aaronson on being this years recipient. When the effort to build quantum computation devices was first seriously explored in the 1990s, some labeled it as science fiction. While the realization of a fully functional quantum computer may still be in the future, this is certainly not science fiction. The successful quantum hardware experiments by Google and others have been a marvel to many who are following these developments. Scott Aaronson has been a leading figure in this area of research and his contributions will continue to focus and guide the field as it reaches its remarkable potential.

Explaining that the goal of quantum computing is:

"to harness the laws of quantum physics to build devices that can solve problems that classical computers either cannot solve, or not solve in any reasonable amount of time"

the ACM notes that Aaronson showed how results from computational complexity theory can provide new insights into the laws of quantum physics, and brought clarity to what quantum computers will, and will not, be able to do.

Aaronson helped develop the concept of quantum supremacy, something that would be achieved when a quantum device can solve a problem that no classical computer can solve in a reasonable amount of time and established many of the theoretical foundations of quantum supremacy experiments. He has also explored how quantum supremacy experiments could deliver a key application of quantum computing, namely the generation of cryptographically random bits.

Among his notable contribution are the 2011 paper The Computational Complexity of Linear Optics, in which, with co-author Alex Arkhipov, he put forward evidence that rudimentary quantum computers built entirely out of linear-optical elements cannot be efficiently simulated by classical computers.

Earlier, in his 2002 paper Quantum lower bound for the collision problem, Aaronson proved the quantum lower bound for the collision problem, which had been for years a major open problem. This work bounds the minimum time for a quantum computer to find collisions in many-to-one functions, giving evidence that a basic building block of cryptography will remain secure for quantum computers.

Aaronson is known for hiswork on algebrization, a technique he invented with Avi Wigderson to understand the limits of algebraic techniques for separating and collapsing complexity classes. Beyond his technical contributions, Aaronson is also credited with making quantum computing understandable to a wide audience, through his popular blog,Shtetl Optimized, where he explains timely and exciting topics in quantum computing in a simple and effective way, TED Talks to dispel misconceptions and provide the public with a more accurate overview of the field and his bookQuantum Computing Since Democritus, see side panel.

In his latest blog post, Aaronson recounts how he was toled about winning the prize and writes:

I dont know if Im worthy of such a prizebut I know that if I am, then its mainly for work I did between roughly 2001 and 2012. This honor inspires me to want to be more like I was back then, when I was driven, non-jaded, and obsessed with figuring out the contours of BQP and efficient computation in the physical universe. It makes me want to justify the ACMs faith in me.

ACM Prize Awarded to Pioneer in Quantum Computing

Dr. Scott J Aaronson

The ACM Prize thing

Scott Aaronson On NP And Physics

David Silver Awarded 2019 ACM Prize In Computing

Authors of the Dragon Book Win 2020 Turing Award

Computer Graphics Pioneers Win 2019 Turing Award

2021 Abel Prize Shared By Math and Computer Science

Knuth Prize 2019 Awarded For Contributions To Complexity Theory

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Scott Aaronson Winner of 2020 ACM Prize In Computing - iProgrammer

Every community guards a creation story, a theory of cosmic origins. In much of sub-Saharan West Africa, for the past few thousand years, itinerant storytellers known as griots have communicated these and other tales through song. Cosmologists also intone a theory of cosmic origins, known as the Big Bang, albeit through journal articles and math.

Chanda Prescod-Weinstein is a cosmologist who is adept with both equations and the keeper of a deeply human impulse to understand our universe. In her first book, The Disordered Cosmos: A Journey into Dark Matter, Spacetime, & Dreams Deferred, Prescod-Weinstein also admits she is a griot, one who knows the music of the cosmos but sings of earthbound concerns. She is an award-winning physicist, feminist, and activist who is not only, as she says, the first Jewish queer agender Black woman to become a theoretical cosmologist, she is the first Black woman ever to earn a Ph.D. in the subject.

BOOK REVIEW The Disordered Cosmos: A Journey into Dark Matter, Spacetime, & Dreams Deferred, by Chanda Prescod-Weinstein (Bold Type Books, 336 pages).

Prescod-Weinsteinis an assistant professor of physics and astronomy, and a core faculty member in the department of womens and gender studies at the University of New Hampshire. She thus enjoys a unique frame of reference from which to appraise science and her fellow scientists. She is an insider whom others nonetheless cast as an outsider, because of her identity, orientation, and the tint of her skin. From the outside, however, she admits a fuller view of her field. She perceives the structures that were invisible to people, and reveals them.

The Disordered Cosmos is equal parts critical analysis, personal essay, and popular science. It is an introspective yet revelatory book about the culture of physics and the formative years of a scientific career.

Growing up during the 1990s in East Los Angeles, where at night the dominant lights flashed red and blue, Prescod-Weinstein owned a telescope but rarely saw the stars. She was a born empiricist who decided to become a physicist at the age of 10, after her single mother took her to see the documentary A Brief History of Time. Her mother, the journalist and wage activist Margaret Prescod, continually nourished the young girls passion. She took a teenage Prescod-Weinstein to Joshua Tree National Park, where they spent a night observing the Comet Hyakutake, unblinded by city lights.

After arriving at Harvard University to study physics, Prescod-Weinstein struggled academically, in part because of her own extracurricular advocacy for providing a living wage to campus workers. Yet a classmate tried to help her realize her childhood dream. He offered her a job at a new observatory atop Maunakea in Hawaii, where the view to the heavens was among the most limpid on Earth. There she could earn better than a living wage in the astronomers efforts to gather photons particles of light that will help them tell our cosmological story.

Prescod-Weinstein imagined dedicating herself to pure physics in this idyllic locale, with beaches, amazing tans, and an opportunity to start over. But no physics is pure, no place such an idyll. Astronomers had started building their telescopes on Maunakea during the 1960s against the protests of native Hawaiians, for whom the summit is sacred. Her living wages, she realized, would have underwritten the erasure of another peoples cosmology. I promised myself that I would make more room in my life for my dreams of being a physicist, she wrote. But not like this. She now supports the native Hawaiians who have vowed to protect their unceded lands against the impending construction of the Thirty Meter Telescope, which might yet become the worlds largest.

Prescod-Weinstein not only narrates her struggle to become a cosmologist, she advocates for all peoples whom physicists have undervalued. She praises the assistants and janitors, mostly people of color, whose labor permits theorists to ponder the universe daily, because part of science is emptying the garbage. She elevates her elders, such as Elmer Imes and Ibn Sahl, whose contributions others have disregarded because these forebears were not of European descent.

The beauty of mathematics and the majesty of the stars attracted Prescod-Weinstein to cosmology. They sustain her. Yet, she writes: Learning about the mathematics of the universe could never be an escape from the earthly phenomena of racism and sexism.

So, Prescod-Weinstein unveils the majesty that oppression obscures. In the opening quarter of her book, she hurries readers through a tour of physics, rushing past Bose-Einstein condensates, axions, and inflatons to arrive at her own research into dark matter. Its a brilliant sprint, and the prize for finishers is some of her finest writing about race and science.

I promised myself that I would make more room in my life for my dreams of being a physicist, Prescod-Weinstein wrote. But not like this.

Prescod-Weinstein includes a thunderous essay about scientists historical neglect of the biophysics of melanin and the repercussions today. Later, there is a chapter that she did not want to write about an episode from her life that she did not want to share. She had no choice, she explained, because Rape is part of science and a book that tells the truth about science would be a lie if I were to leave out this chapter. Her account is so fierce and switches registers so regularly, as if gliding between chorus and verse, that the writing becomes incantatory. She saps the events power to define her, transmuting pain into affecting prose.

Prescod-Weinstein is attuned to the language of physicists, especially the biases it elides, as when her colleagues speak of colored physics, more commonly known as quantum chromodynamics, which she describes as a theory that uses color as an analogy for physical properties that have nothing to do with color. She is adept at then rephrasing physics to redress those biases. Systemic racism is compared to weak gravitational lensing, the subtle distortion of light owing to the curvature space and time around distant galaxies. Cyclical time is intuitive to a person who menstruates. The wave-particle duality reveals the queer, nonbinary nature of quantum mechanics. Dark matter is not actually dark: Its transparent more like a piece of glass than a chalkboard. Not only is the name antithetical to the science, some physicists have compared such invisible matter, crudely, to Black people.

Studying the physical world requires confronting the social world, Prescod-Weinstein writes. It means changing institutionalized science, so that our presence is natural and our cultures are respected. It also means confronting the privileged stories of science.

The demographics of physicists still reflect the iniquities of the past. And physics remains diminished because of its biases. Whenever we exclude whole peoples, we not only disallow their questions we disavow their knowledge. The field squanders other cultures perceptions of time. And as Prescod-Weinstein notes, physicists may even misinterpret the wave-particle duality and confuse the rotating identities of neutrinos because they are too oriented toward binaries.

Learning about the mathematics of the universe could never be an escape from the earthly phenomena of racism and sexism.

The Disordered Cosmos is not perfect. There are phrases that Prescod-Weinstein might have heated longer or squeezed harder until they crystalized. There are intervals when the pressure of having to cite so many ideas make matters too dense. But these are quibbles. Besides, the defects of an otherwise ideal crystal can render it more colorful and electric.

Prescod-Weinstein aspires to loftier matters. The books frontispiece is a sketch of two women who remind her that even in the worst conditions, Black women have looked up at the night sky and wondered. These women were slaves, who not only navigated the stars to freedom but also wondered at that black expanse. They are as much my intellectual ancestors as Isaac Newton is.

Prescod-Weinsteins most vital work, in the end, is the emancipation of Black and brown children who still cannot see their futures in the stars. She distills this labor in a series of questions: What are the conditions we need so that a 13-year-old Black kid and their single mom can go look at a dark night sky, away from artificial lights, and know what they are seeing? What health care structures, what food and housing security are needed?

Prescod-Weinstein teaches that all humans are made of luminous matter. And she knows just how radiant people can be, despite the obstacles in their way. She understands, intimately, that Black people hunger for a connection to scientific thought and will overcome the barriers placed in front of them in order to learn more.

Joshua Roebke is finishing a book on the social and cultural history of particle physics, titled The Invisible World. He won a Whiting Foundation Creative Nonfiction Grant and teaches literature and writing at the University of Texas at Austin.

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Book Review: A Cosmologist Throws Light on a Universe of Bias - Undark Magazine

A minimal Weyl semimetal

Many compounds have now been identified as Weyl semimetals, materials with an unusual electronic band structure characterized by the so-called Weyl points. Weyl points always appear in pairs, but the solid-state materials studied so far have at least four. Wang et al. engineered a Weyl semimetallic state with the minimum number of Weyl points (two) in a gas of ultracold atoms trapped in an optical lattice (see the Perspective by Goldman and Yefsah). To do that, the researchers had to create three-dimensional spin-orbit coupling in this system. The relative simplicity of the resulting band structure will make it easier to observe the unusual effects associated with this state.

Science, this issue p. 271; see also p. 234

Weyl semimetals are three-dimensional (3D) gapless topological phases with Weyl cones in the bulk band. According to lattice theory, Weyl cones must come in pairs, with the minimum number of cones being two. A semimetal with only two Weyl cones is an ideal Weyl semimetal (IWSM). Here we report the experimental realization of an IWSM band by engineering 3D spin-orbit coupling for ultracold atoms. The topological Weyl points are clearly measured via the virtual slicing imaging technique in equilibrium and are further resolved in the quench dynamics. The realization of an IWSM band opens an avenue to investigate various exotic phenomena that are difficult to access in solids.

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Realization of an ideal Weyl semimetal band in a quantum gas with 3D spin-orbit coupling - Science Magazine