Daily Archives: August 14, 2023

Unraveling the mystery of insulator-to-metal transitions, new research into the quantum avalanche uncovers new insights into resistive switching and offers potential breakthroughs in microelectronics.

New Study Solves Mystery on Insulator-to-Metal Transition

A study explored insulator-to-metal transitions, uncovering discrepancies in the traditional Landau-Zener formula and offering new insights into resistive switching. By using computer simulations, the research highlights the quantum mechanics involved and suggests that electronic and thermal switching can arise simultaneously, with potential applications in microelectronics and neuromorphic computing.

Looking only at their subatomic particles, most materials can be placed into one of two categories.

Metals like copper and iron have free-flowing electrons that allow them to conduct electricity, while insulators like glass and rubber keep their electrons tightly bound and therefore do not conduct electricity.

Insulators can turn into metals when hit with an intense electric field, offering tantalizing possibilities for microelectronics and supercomputing, but the physics behind this phenomenon called resistive switching is not well understood.

Questions, like how large an electric field is needed, are fiercely debated by scientists, like University at Buffalo condensed matter theorist Jong Han.

I have been obsessed by that, he says.

Han, PhD, professor of physics in the College of Arts and Sciences, is the lead author on a study that takes a new approach to answer a long-standing mystery about insulator-to-metal transitions. The study, Correlated insulator collapse due to quantum avalanche via in-gap ladder states, was published in May in Nature Communications.

University at Buffalo physics professor Jong Han is the lead author on a new study that helps solve a longstanding physics mystery on how insulators transition into metals via an electric field, a process known as resistive switching. Credit: Douglas Levere, University at Buffalo

The difference between metals and insulators lies in quantum mechanical principles, which dictate that electrons are quantum particles and their energy levels come in bands that have forbidden gaps, Han says.

Since the 1930s, the Landau-Zener formula has served as a blueprint for determining the size of electric field needed to push an insulators electrons from its lower bands to its upper bands. But experiments in the decades since have shown materials require a much smaller electric field approximately 1,000 times smaller than the Landau-Zener formula estimated.

So, there is a huge discrepancy, and we need to have a better theory, Han says.

To solve this, Han decided to consider a different question: What happens when electrons already in the upper band of an insulator are pushed?

Han ran a computer simulation of resistive switching that accounted for the presence of electrons in the upper band. It showed that a relatively small electric field could trigger a collapse of the gap between the lower and upper bands, creating a quantum path for the electrons to go up and down between the bands.

To make an analogy, Han says, Imagine some electrons are moving on a second floor. When the floor is tilted by an electric field, electrons not only begin to move but previously forbidden quantum transitions open up and the very stability of the floor abruptly falls apart, making the electrons on different floors flow up and down.

Then, the question is no longer how the electrons on the bottom floor jump up, but the stability of higher floors under an electric field.

This idea helps solve some of the discrepancies in the Landau-Zener formula, Han says. It also provides some clarity to the debate over insulator-to-metal transitions caused by electrons themselves or those caused by extreme heat. Hans simulation suggests the quantum avalanche is not triggered by heat. However, the full insulator-to-metal transition doesnt happen until the separate temperatures of the electrons and phonons quantum vibrations of the crystals atoms equilibrate. This shows that the mechanisms for electronic and thermal switching are not exclusive of each other, Han says, but can instead arise simultaneously.

So, we have found a way to understand some corner of this whole resistive switching phenomenon, Han says. But I think its a good starting point.

The study was co-authored by Jonathan Bird, PhD, professor and chair of electrical engineering in UBs School of Engineering and Applied Sciences, who provided experimental context. His team has been studying the electrical properties of emergent nanomaterials that exhibit novel states at low temperatures, which can teach researchers a lot about the complex physics that govern electrical behavior.

While our studies are focused on resolving fundamental questions about the physics of new materials, the electrical phenomena that we reveal in these materials could ultimately provide the basis of new microelectronic technologies, such as compact memories for use in data-intensive applications like artificial intelligence, Bird says.

The research could also be crucial for areas like neuromorphic computing, which tries to emulate the electrical stimulation of the human nervous system. Our focus, however, is primarily on understanding the fundamental phenomenology, Bird says.

Since publishing the paper, Han has devised an analytic theory that matches the computers calculation well. Still, theres more for him to investigate, like the exact conditions needed for a quantum avalanche to happen.

Somebody, an experimentalist, is going to ask me, Why didnt I see that before? Han says. Some might have seen it, some might not have. We have a lot of work ahead of us to sort it out.

Reference: Correlated insulator collapse due to quantum avalanche via in-gap ladder states by Jong E. Han, Camille Aron, Xi Chen, Ishiaka Mansaray, Jae-Ho Han, Ki-Seok Kim, Michael Randle and Jonathan P. Bird, 22 May 2023, Nature Communications. DOI: 10.1038/s41467-023-38557-8

Other authors include UB physics PhD student Xi Chen; Ishiaka Mansaray, who received a PhD in physics and is now a postdoc at the National Institute of Standards and Technology; and Michael Randle, who received a PhD in electrical engineering and is now a postdoc at the Riken research institute in Japan. Other authors include international researchers representing cole Normale Suprieure, French National Centre for Scientific Research (CNRS) in Paris; Pohang University of Science and Technology; and the Center for Theoretical Physics of Complex Systems, Institute for Basic Science.

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Quantum Avalanche A Phenomenon That May Revolutionize Microelectronics and Supercomputing - SciTechDaily

Summer 2023 in the Northern Hemisphere is on track to be the hottest on record, and the sun is blazing in the sky. One way to deal with it is to slap on the sunscreen. But have you ever thought about how sunscreen actually works? It all comes down to how photons from the sun interact with our skin.

Photons are the messenger particles of the electromagnetic forceone of the four fundamental forces of natureand are responsible for an array of phenomena including the X-rays we use to examine broken bones, the microwaves we use to reheat food, and, probably most importantly for many people, the visible light we use to see.

During summer, we receive the maximum flux of photons from the sun due to the Earths slight tilt in its direction. At roughly the latitude of Chicago, the flux of photons is three times greater at midday in the peak of summer than during midwinter.

The sun emits photons in all parts of the electromagnetic spectrum, but the majority are from the visible, infrared and ultraviolet segments. Ultraviolet radiation plays an essential role in maintaining plant and animal life, but it has also consistently been identified as a cause of skin cancer. Understanding why is the first step to understanding how sunscreen protects us from it.

UV radiation has a higher frequency than visible or infrared light, which means that, of the three types, UV photons have the most energy. When UV photons hit your skin, their energy has to go somewhere. (Even in the summertime, no one gets a holiday from conserving energy.) In the absence of protection, this energy is transferred to the fats and proteins in your skin. The excess energy is capable of triggering mutations in our DNA, which are a cause of skin cancer.

While our bodies do possess some natural protective mechanisms against UV radiation, the prevalence of skin cancer (along with painful sunburns) clearly demonstrates that it is necessary to enhance these mechanisms artificially.

Enter sunscreen.

The active ingredients of sunscreen fall into two main categories: organic molecules and inorganic crystals. Both of these components act by absorbing UV radiation like a sponge and then dissipating it safely into the environment. How does this work? It all has to do with electrons and quantum mechanics.

As you may remember from chemistry classes, electrons in atoms and molecules occupy orbitals i.e., discrete energy levels. An electron stays put in its home orbital unless it absorbs the right amount of energy to jump up to the next one. Because of this, an electron cant contain any old amount of energyonly specific, quantized amounts. This is where the quantum comes from in quantum mechanics, which includes the study of quantized energy in subatomic particles.

The inorganic compounds in sunscreen have a crystalline structure and contain (mostly) free electrons. These electrons are constantly buzzing around and interacting, which creates a flexible orbital structure called a band gap.

The band presents a loophole to the quantized energy problem in quantum mechanics because it allows electrons to absorb a wide spectrum of energies. (After all, theres not just a single dangerous wavelength of light from the sun.)

In isolated atoms, you have pretty sharp, quantized transitions between atomic orbitals, says Thomas Wolf, a physical chemist at the US Department of Energys SLAC National Accelerator Laboratory. If you now have many atoms in a lattice like in an inorganic sunscreen, their atomic orbitals can overlap. This leads to many quantized transitions, which are fairly similar in energy and form bands. If light gets absorbed, electrons get promoted from an occupied to an unoccupied band across a band gap.

When UV photons from the sun hit inorganic sunscreen, the electrons dash from the lower orbitals into the excited orbitals, each jumping a distance equivalent to the energy of the photon that excited it. After a while, the excited electrons drop back down to their original orbitals, releasing the energy they absorbed as heat.

Organic sunscreens work in a similar way, but their active ingredients have no band gaps. Instead, they use the beauty of covalent bonds and hybridized orbitals.

Covalent bonds form when an electron is shared almost evenly between two atoms, and this creates orbital hybridization (the mixing and merging of two independent atomic orbitals into a new super orbital, so to speak). Organic sunscreens use rings and chains of covalently bonded carbon atoms to play with the distance between these new ground and excited states. Combining many different molecules with many different orbital configurations allows organic sunscreens to protect the skin against many different wavelengths of light.

There is ongoing research to find the most efficient mechanism for the excited electrons in sunscreen to release their energy, with researchers taking inspiration from the mechanisms that plants use to protect themselves from the sun. Scientists are also researching how to make organic sunscreens hardier, since over time and after atoms have absorbed a certain amount of energy, the bonds between them can snap.

So there you have it, the science behind sunscreen. To all you physics students out there: Even on the beach, you are still applying quantum mechanics, literally to your skin!

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Applications of quantum mechanics at the beach - Symmetry magazine

This book is for readers with an interest in physics and astronomy. While some concepts are difficult, no knowledge of physics or mathematics is needed.

On the Origin of Time Stephen Hawkings Final Theory

Thomas Hertog, Bantam New York, 313 pages

This is not a book for a leisurely afternoon read in the car while waiting to pick up the kids after hockey practice. It needs concentration and a willingness to reread some passages, dealing as it does to a large extent with aspects of quantum physics, which by itself often requires a suspension of disbelief.

Not a very enthusiastic opening statement for a book review you may think, but readers who persevere will be more than richly rewarded with insights into some of the most exciting concepts in modern cosmology.

The author was for a long time a collaborator and friend of Stephen Hawking, who certainly needs no introduction. His admiration for his late colleague shines from almost every page.

Together they spent years theorizing about the universes biophilic nature (a word Hertog clearly likes), that is to say, why is our cosmos so apparently fine-tuned for life. Change just one or two of many physical constants by miniscule amounts and we wont be here to discuss this phenomenon.

Why is this so? Hawking and Hertog werent the first to examine this and wont be the last. This book describes their thoughts in fascinating and almost overwhelming detail.

Various theories have been proposed to explain this, some gaining general acceptance, others seemingly outlandish even when finding favour in the physics community. After all, when a theory states that every time something happens the universe splits into consecutively multiplying and different multiverses, not in contact with each other, some where the observer adds sugar to coffee and some adding salt, or adding nothing at all (or a gazillion other possibilities), it may be hard to take seriously.

The thing is: the two-split experiment (see link at the end), which is fundamental to quantum theory and which has been proved multiple times, is one of the strangest concepts I know, but the phenomenon it illustrates is real so what must one make of these strange theories which also involve quantum physics?

Hertog starts his walk through the cosmos with the big bang and the Belgian astronomer-priest Georges Lematre, explaining Hawkings no-boundary theory of time folding into space, ceasing to exist at the very beginning of the universe. We are then told about the quantum soup of particles which emerged, ending with the realization that the laws of physics as we know them today probably emerged right at the beginning, having been subject to what one may perhaps call natural selection in the style of Darwin.

Hawking has disowned his bestselling Brief History of Time of some years ago, and together with Hertog devised what he calls top-down cosmology. This viewpoint holds (inter alia) that the nature and course of development of the universe is influenced by observers, which are often and incorrectly stated by some journalists to be humans. This need not be the case, a casual glance by a mouse will suffice, or an electron hitting a crystal.

This state of affairs is (for me) somewhat reminiscent of the anthropic principle, although Hertog never mentions it.

We end with the realization that the universe may be a hologram: At a conceptual level, holography seals the top-down approach to cosmology. The central tenet of holographic cosmology that the past projects from a web of entangled quantum particles that form a lower-dimensional hologram implies a top-down view of the universe. Holography tells us that there is an entity more basic than time a hologram from which the past emerges.

Whatever ones opinion of the Hawking-Hertog universe may be, I find one aspect deeply satisfying: previously cosmologists looked at the universe as if from the outside in. Hawking and Hertogs perspective is from the inside we are part of the universe, not separate from it.

This book is for readers with an interest in physics and astronomy. While some concepts are difficult, no knowledge of physics or mathematics is needed.

Anyone who wants to find out more about the double slit experiment can watch this video: https://www.youtube.com/watch?v=A9tKncAdlHQ.

The views and opinions expressed in this article are those of the author, and do not necessarily reflect the position of this publication.

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Book Review: On the Origin of Time Stephen Hawking's Final Theory - Moose Jaw Today

Harnessing Quantum Technologies: The Next Big Leap in Global Telecommunications

The world of telecommunications is on the brink of a revolutionary transformation, thanks to the advent of quantum technologies. This cutting-edge technology, which exploits the principles of quantum mechanics, is set to redefine the way we communicate, offering unprecedented speed, security, and efficiency.

Quantum technology is a complex and fascinating field that leverages the peculiar properties of quantum physics. At its core, it involves the manipulation of individual particles like atoms, electrons, and photons to create advanced technological systems. The potential applications of this technology are vast and varied, but its implications for the telecommunications sector are particularly profound.

One of the most promising applications of quantum technology in telecommunications is quantum key distribution (QKD). This technology uses the principles of quantum mechanics to create unbreakable encryption keys, ensuring the secure transmission of information. In a world where data breaches and cyber-attacks are increasingly common, the importance of this cannot be overstated. QKD could provide a level of security that is currently unattainable with traditional encryption methods, making it a game-changer for industries that rely heavily on secure communications, such as finance, healthcare, and defense.

Another exciting development is the prospect of quantum internet. This would involve using quantum entanglement, a phenomenon where particles become interconnected and can instantly affect each other regardless of distance, to transmit information. This could potentially allow for instantaneous communication across vast distances, revolutionizing global connectivity. While this technology is still in its infancy, the potential implications are staggering.

The advent of quantum technologies also promises to enhance the capacity and speed of telecommunications networks. Quantum bits, or qubits, can exist in multiple states at once, unlike traditional bits that can only be in one state at a time. This means that quantum computers could process information much faster than their classical counterparts, potentially leading to a dramatic increase in network speeds.

However, harnessing quantum technologies is not without its challenges. The technology is still in its early stages, and there are significant technical hurdles to overcome. Quantum systems are extremely sensitive to environmental disturbances, making them difficult to stabilize and control. Moreover, the technology requires significant investment in infrastructure and research, which may be prohibitive for some countries and companies.

Despite these challenges, the potential benefits of quantum technologies are too significant to ignore. Governments and corporations around the world are investing heavily in quantum research and development, recognizing its potential to transform the telecommunications landscape.

In conclusion, quantum technologies represent the next big leap in global telecommunications. They promise to revolutionize the way we communicate, offering unprecedented speed, security, and efficiency. While there are significant challenges to overcome, the potential benefits are too significant to ignore. As we stand on the brink of this technological revolution, it is clear that the future of telecommunications lies in the quantum realm.

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Harnessing Quantum Technologies: The Next Big Leap in Global ... - Fagen wasanni

These are very special diamonds that are being worked with at TU Wien: Their crystal lattice is not perfectly regular, it contains numerous defects. In places where there would be two neighboring carbon atoms in a perfect diamond, there is a nitrogen atom, leaving the second place empty. Microwaves can be used to switch these defects between two different states - a higher energy state and a lower energy state. This makes them an interesting tool for various quantum technologies, such as novel quantum sensors or components for quantum computers.

Now, the researchers have succeeded in controlling these defects so precisely that they can be used to trigger a spectacular effect: All defects are brought into the high-energy state, in which they remain for some time, until one then releases all the energy with a tiny microwave pulse and all defects simultaneously change to the low-energy state - similar to a snowfield on which a tiny snowball triggers an avalanche and the entire mass of snow thunders down into the valley at the same time.

Computer visualization of the microwave resonator with superconducting chips and diamond (black). The silver wave represents the quantum avalanche - the sudden emission of an electromagnetic pulse.

"The defects in the diamond have a spin - an angular momentum that points either up or down. These are the two possible states they can be in," says Wenzel Kersten, first author of the current publication, who is currently working on his dissertation in the research group of Prof. Jrg Schmiedmayer (Atomic Institute, Vienna University of Technology).

With the help of a magnetic field, one can achieve that, for example, the "spin up" state corresponds to a higher energy than "spin down." In this case, most atoms will be in the "spin down" state - they normally gravitate to the lower energy state, like a ball in a bowl that normally rolls downward.

But with some clever engineering tricks, it's possible to create what's called an "inversion" - you get the defects to all settle into the higher energy state. "You use microwave radiation for this, by which you first bring the spins into the desired state, then you change the external magnetic field so that the spins are frozen in this state, so to speak," explains Prof. Stefan Rotter (Institute for Theoretical Physics, Vienna University of Technology), who led the theoretical part of the research.

Such an "inversion" is unstable. In principle, the atoms could spontaneously change their state - similar to balancing a broomstick, which in principle can spontaneously tip over in any direction. But the research team was able to show: Extremely precise control, made possible by chip technology developed at TU Wien, can keep the spins of the atoms stable for about 20 milliseconds. "By quantum physics standards, that's a huge amount of time. That's about a hundred thousand times as long as it takes to create this high-energy state or to discharge it again. That's like having a cell phone battery that is charged in an hour and then holds its energy completely for ten years," says Jrg Schmiedmayer.

During this time, however, it is possible to bring about the change of state in a targeted manner - and to do so by means of a very small, weak cause, such as a microwave pulse of minimal intensity. "It causes an atom to change its spin, whereupon neighboring atoms also change their spin - thus creating an avalanche effect. All the energy is released, in the form of a microwave pulse that is about a hundred billion times stronger than the one used to trigger the effect originally," explains Stefan Rotter. "That is proportionally as if a single snowflake were to trigger a snow slab weighing several hundred tons."

This offers many interesting possibilities: For example, one can amplify weak electromagnetic pulses in this way, one could use this for special sensors, one can use it to create a kind of "quantum battery" with which a certain amount of energy can be stored and released in a targeted manner at the quantum level.

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The quantum avalanche - At the Vienna University of Technology, it ... - Chemie.de

Exploring the Role of Semiconductors in Quantum Computing: The Future of AI

Semiconductors, the tiny chips that power our modern world, are poised to play a pivotal role in the future of artificial intelligence (AI) and quantum computing. As the linchpin of these advanced technologies, semiconductors are set to revolutionize the way we process and analyze data, opening up new possibilities for innovation and growth.

Quantum computing, a field that leverages the principles of quantum mechanics, promises to solve complex problems that are currently beyond the reach of classical computers. At the heart of this technology are quantum bits, or qubits, which can exist in multiple states at once, enabling them to perform multiple calculations simultaneously. This is where semiconductors come into play.

Semiconductors are materials that have a conductivity level somewhere between conductors, like copper and gold, and insulators, like glass and rubber. They are used to make integrated circuits, or chips, which are the building blocks of all modern electronic devices. In the context of quantum computing, semiconductors are used to create qubits.

The use of semiconductors in quantum computing is not without its challenges. Qubits are extremely sensitive to their environment, and even the slightest disturbance can cause them to lose their quantum state, a phenomenon known as decoherence. However, researchers are making strides in overcoming these obstacles. For instance, they are developing new semiconductor materials and designs that can maintain qubits in their quantum state for longer periods, thereby increasing the computational power of quantum computers.

The implications of these advancements for AI are profound. AI relies on the processing and analysis of vast amounts of data to make predictions, recognize patterns, and learn from experience. Quantum computers, powered by semiconductor-based qubits, could process this data exponentially faster than classical computers, thereby supercharging AI capabilities.

Moreover, the integration of AI and quantum computing could lead to the development of new algorithms that can solve complex problems more efficiently. For example, quantum machine learning, a subfield of AI that combines machine learning with quantum physics, could potentially revolutionize fields such as drug discovery, climate modeling, and financial optimization.

In addition, the use of semiconductors in quantum computing could also lead to significant energy savings. Quantum computers are expected to be much more energy-efficient than classical computers, which could help reduce the carbon footprint of data centers, which currently account for about 2% of global greenhouse gas emissions.

In conclusion, semiconductors are set to play a crucial role in the future of AI and quantum computing. As researchers continue to make breakthroughs in this field, we can expect to see a new era of computing that is faster, more efficient, and more powerful than ever before. The integration of AI and quantum computing, powered by semiconductors, holds the promise of solving some of the worlds most complex problems, and transforming industries across the board.

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Semiconductors: The Linchpin of AI in Quantum Computing - Fagen wasanni

Dennis Nemeschansky, professor of physics and astronomy at USC Dornsife College of Letters, Arts and Sciences, died on June1. He was 67.

An expert on string theory who focused on supersymmetry quantum field theory, Nemeschansky is best known for the Minahan-Nemeschansky Theory, which he developed with visiting physicist Joseph Minahan during a game of golf.

Published in 1997, their paper showed that the then-current approach to constructing certain types of important supersymmetric quantum field theories was incorrect and demonstrated the correct way to do it. Initial skepticism from the scientific community gradually gave way to respect and acceptance a decade later, as the theory continued to hold true under scrutiny.

Moreover, they were able to generalize their result to construct several more theories that completed a connection between these supersymmetric quantum field theories and a deep mathematical classification result.

Nemeschanskys teaching focused on pre-med physics, and he taught Physics for the Life Sciences (PHYS 135) for more than 30 years.

Stephan Haas, chair of the Department of Physics and professor of physics and astronomy, said Nemeschansky would be sorely missed by faculty and students alike.

Dennis had a great sense of humor, passion for science and ability to communicate complex material in a very understandable way, Haas said.

Indeed, Nemeschansky wasnt shy about using his considerable athleticism to illustrate the properties of physics to his students and could be spotted each semester demonstrating Newtons Third Law by whizzing across campus on a skateboard with a fire extinguisher attached.

Students and colleagues loved his casual and relatable attitude, Haas said. In his research, he made seminal contributions to our understanding of quantum field theory and string theory, their application to unification of forces, and on strong-weak coupling duality in supersymmetric quantum chromodynamics.

A true calling

Nemeschansky was born in Helsinki, Finland, on Dec. 21, 1955. His father, Arje, was a salesman of kitchen equipment and his mother, Joan, worked in pharmaceutical sales. Nemeschansky was brought up in the Jewish faith, attending Hebrew school in Helsinki.

His son, alumnus David Nemeschansky 15, who earned undergraduate degrees in political science from USC Dornsife and in communication from USC Annenberg School for Communication and Journalism as well as a progressive masters from USC Leventhal School of Accounting, said his father was one of the lucky few blessed with a true calling in life.

He always knew from a very young age that math and physics were his thing, he said. It actually made his parents very nervous because he just wanted to do numbers and really had no patience or interest in any other subject.

After completing his national service in the Finnish Army, Nemeschansky obtained an MSc in theoretical physics from Helsinki University of Technology in 1980. He then moved to the United States to earn his PhD at Princeton University in 1984, where he collaborated with and was taught by some of the leading physics minds of the day. It was also where he decided to study string theory, which he specialized in throughout his career.

After Princeton, he moved to Stanford University, where he completed his postdoctoral training at the Stanford Linear Accelerator Center in 1986.

The move to California proved decisive.

Coming from Finlands cold, dark winters, he fell in love with the sunny paradise of California and really wanted to stay here, said David Nemeschansky.

The promising young physicist was invited to give a talk at USCs inaugural string theory conference in 1985 and joined USC Dornsife the following year.

He had this personality where he wanted things done right 98% wasnt good enough.

He was recruited with Itzhak Bars, professor of physics and astronomy, to create a new theoretical physics group within the department.

Most of these new hires were string theorists. My father was really excited about that and the possibility of working with those folks and building out something new at USC, David Nemeschansky said.

A devoted teacher and mentor to his students, Nemeschansky took office hours very seriously, offering more than was required of him.

He believed that you had to really understand physics and the mathematical backing behind it; you couldnt just memorize formulas, David Nemeschansky said. He felt very strongly that people need to be taught in a way that shows them that beauty and elegance. And then they would never have to memorize a formula; they would see how it all ties together.

While David Nemeschansky was a student at USC, he remembers his father inviting him to attend a lecture in which he would demonstrate how the entire physics textbook could be derived from two formulas. I remember watching people in the first 15 minutes meticulously taking notes as hes doing all these graphs on the chalkboard he had no notes, it was all in his head. And then you could slowly see the atmosphere in the room turn to awe because it was very clear that his understanding was so deep.

Disinterested in becoming department chair because he preferred to concentrate on his teaching and research, Nemeschansky did serve as colloquium chair, organizing physics symposiums and bringing in expert speakers to talk to faculty and doctoral students. He also served as scheduling chair, compiling the departments class schedules.

In 1995 and 2004, he was a visiting fellow at the European Organization for Nuclear Research on the French-Swiss border, the location of the worlds most powerful particle accelerator. He also spent the summer of 2018 at TRIUMF in Canada.

Prior to his death, Nemeschansky wrote a physics textbook tailored to health students with USC Dornsifes Scott Macdonald, assistant professor (teaching) of physics and astronomy. MacDonald is currently in talks with a publisher.

A passion for family, physics, sports and books

David Nemeschansky remembers being impressed by his fathers extensive library.

I used to joke that in his office he had a wizard library. He really was trying to figure out the great mysteries of the universe, how matter is constructed, how the tiniest subatomic particles work. How many dimensions are there? How did the universe begin?

In addition to his life-long passion for physics, Nemeschansky was a huge sports enthusiast.

My father was a man of a very clear priorities: family, physics and sports in that order, said David Nemeschansky.

He was a keen ice hockey player and was so talented at tennis that at university he had to choose between a professional career in the sport and physics. His love of physics won.

Nemeschansky was also a talented soccer player and became an avid golfer in middle age.

He had this personality where he wanted things done right 98% wasnt good enough, David Nemeschansky said. He had immensely high standards for instance, he would rather not publish than publish something that was mediocre. That exacting nature translated into sports.

He really wanted me to have outstanding hockey training and he felt he was the only person who could do that, so he became my coach.

The modest Finn

Nemeschansky may have been a perfectionist, but by all accounts, he was also an extremely modest, private man who asked students to call him by his first name.

He is fondly remembered by faculty, staff and students as a brilliant but self-effacing man who inevitably had an undone shoelace.

He was a man of few words. He didnt really talk much about himself unless asked and even then, if you asked him where he went to school, he would say back East. He wouldnt say Princeton, said David Nemeschansky.

Nemeschansky spoke fluent Finnish, Swedish and English and some Hebrew.

A believer in Judaism who saw ample room for God and physics to go hand in hand, Nemeschansky regularly attended synagogue.

In 1988, he married Lauren Rosen, a grade schoolteacher who later became a successful realtor.

Nemeschansky loved to travel and enjoyed photographing waterfalls so much his family nicknamed him Captain Tripod.

He retained great affection for the country of his birth throughout his life despite feeling it was a little small.

He had bigger dreams, and that eventually took him to the U.S., said David Nemeschansky. He married an American, had American children, but he stayed a Finnish citizen until he died. He loved his country.

Nemeschansky is survived by his mother; his wife; his sons, David and Marc; and his brothers, Ben and Michael.

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String theory physicist changed quantum field theory - USC Dornsife College of Letters, Arts and Sciences

The combination of artificial intelligence (AI) and quantum computing holds immense potential for groundbreaking discoveries and advancements in various fields. Quantum computing can revolutionize medicine by finding cures for diseases like cancer and Alzheimers, as well as contribute to clean energy solutions with environmental benefits. Moreover, quantum computing complements AIs ability to self-improve and learn from mistakes by adding speed and power.

Previously, AI development experienced an AI winter, where it was overhyped and fell short of its potential. However, recent advancements in generative AI have signaled a new era for machine learning. A similar trajectory is expected for quantum computing, with Professor Giulio Chiribella, director of the Quantum Information and Computation Initiative at the University of Hong Kong, describing it as a remarkable achievement of human ingenuity and knowledge.

Efforts to develop functional quantum computers are underway globally, with significant investments from both the private sector and governments. China, for instance, has invested around $25 billion in quantum computing since the mid-1980s. However, building a practical quantum computer is a monumental challenge. Unlike classical computers, which use bits as binary digits of information, quantum computers utilize qubits (quantum bits). Qubits can exist in multiple states simultaneously due to the nature of quantum physics, making them inherently more complex.

Managing and controlling qubits is difficult due to their fragile nature and susceptibility to interference. Maintaining quantum computers at ultralow temperatures near absolute zero helps preserve qubits stability. Overcoming noise challenges and achieving decoherence is a significant obstacle in quantum computing.

Despite these challenges, quantum computing has the potential to surpass classical computers in terms of speed and power. While classical computers process information linearly, quantum computers can perform multiple calculations simultaneously. This exponential increase in computing capabilities could enable complex calculations that would take classical supercomputers thousands of years to complete in a matter of minutes.

Understanding the potential impact of quantum computing requires some knowledge of quantum physics. The field itself is perplexing and counterintuitive, but it offers a new perspective on the fundamental workings of the universe. Quantum mechanics introduced concepts such as superposition and entanglement, which defy classical notions of reality.

In summary, the collaboration between AI and quantum computing holds great promise for scientific breakthroughs and technological advancements. While challenges remain in developing functional quantum computers, the potential benefits make it a field worth exploring and investing in.

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The Promising Collaboration Between AI and Quantum Computing - Fagen wasanni

The words Quantum and Supercomputer are really big words. The former refers to a completely different world, whereas the latter refers to computers that are significantly faster and better than average robots. When we join these two words, it forms something extraordinary. A highly efficient computer that uses completely different principles to execute commands that for usual computers, would be impossible.

What are Quantum Supercomputers? They are very powerful and cutting-edge computers that work considerably more quickly than conventional computers thanks to the laws of quantum physics. Developers along with engineers made these computers to solve problems that were very complex for our regular computers (Complex problems here are problems with lots of variables interacting in complicated ways). Problems regarding how atoms are interacting in molecules or how a nuclear reaction will be executed involve multiple factors, which is what makes it so incomprehensible for regular computers.

How does it work? Well, bad news for you, the first and most important thing is the relatively hardest part to understand. Took me a few days of research to understand these, but Ill make it simple. Lets call Quantum Supercomputers QS. So, how is a QS different from a regular laptop? Well, it eliminates the boundaries of processing. Now, why do I say this? Well, as the nerdy computer people may know, our regular computers work by assigning binary units of information to bits, represented as either a 0 or a 1. So, one piece of information has been assigned to a specific number (0 or 1). Well, QS just breaks this barrier. In the QS world, we use qubits instead of bits. And due to a property called Quantum Superposition, qubits can exist as 0 and 1 simultaneously. Confusing, isnt it? Well, take the example of a doughnut shop. You are the customer and the doughnut vendor is the seller. Now, you buy the doughnut from the seller, so your job is buying a doughnut, and his job is selling the doughnut, right? Well, according to Quantum Superposition, you can be both the seller and the buyer!

This was just one of the factors which increase the speed of computation in a QS. An increase in qubits leads to an increase in computational speed. It is estimated that a quantum computer with 100 qubits could theoretically be 10000000000000000000000000000000 (10 to its 30th power) times faster than a classical computer! And with these high speeds, cooling is vital. Ever heard of absolute zero? Its the temperature at which its so cold that particles of matter stop moving. These machines require about a hundredth of a degree (0.01) above absolute zero!

WHERE are these QS used? Well, these computers can be used for complex calculations. These types of calculations are mainly found in Quantum Simulation, Cryptography, Machine Learning, Quantum Chemistry, Financial Modeling, and more. The field of optimisation is another important application area. Quantum computers are incredibly effective at solving optimisation problems because they can explore multiple possibilities at once.

Despite these impressive applications, actual quantum computers are still constrained by qubit count and error rates. These constraints are expected to be abolished as technology advances, allowing for even more applications in a variety of fields. In the future years, quantum computing has the potential to redefine problem-solving and promote innovation, presenting unprecedented opportunities for tackling difficulties that are intractable for traditional computers.

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QUANTUM SUPERCOMPUTERS. The words Quantum and ... - Medium

In 2022, nine MIT faculty were granted tenure in the School of Science:

Gloria Choi examines the interaction of the immune system with the brain and the effects of that interaction on neurodevelopment, behavior, and mood. She also studies how social behaviors are regulated according to sensory stimuli, context, internal state, and physiological status, and how these factors modulate neural circuit function via a combinatorial code of classic neuromodulators and immune-derived cytokines. Choi joined the Department of Brain and Cognitive Sciences after a postdoc at Columbia University. She received her bachelors degree from the University of California at Berkeley, and her PhD from Caltech. Choi is also an investigator in The Picower Institute for Learning and Memory.

Nikta Fakhri develops experimental tools and conceptual frameworks to uncover laws governing fluctuations, order, and self-organization in active systems. Such frameworks provide powerful insight into dynamics of nonequilibrium living systems across scales, from the emergence of thermodynamic arrow of time to spatiotemporal organization of signaling protein patterns and discovery of odd elasticity. Fakhri joined the Department of Physics in 2015 following a postdoc at University of Gttingen. She completed her undergraduate degree at Sharif University of Technology and her PhD at Rice University.

Geobiologist Greg Fournier uses a combination of molecular phylogeny insights and geologic records to study major events in planetary history, with the hope of furthering our understanding of the co-evolution of life and environment. Recently, his team developed a new technique to analyze multiple gene evolutionary histories and estimated that photosynthesis evolved between 3.4 and 2.9 billion years ago. Fournier joined the Department of Earth, Atmospheric and Planetary Sciences in 2014 after working as a postdoc at the University of Connecticut and as a NASA Postdoctoral Program Fellow in MITs Department of Civil and Environmental Engineering. He earned his BA from Dartmouth College in 2001 and his PhD in genetics and genomics from the University of Connecticut in 2009.

Daniel Harlow researches black holes and cosmology, viewed through the lens of quantum gravity and quantum field theory. His work generates new insights into quantum information, quantum field theory, and gravity. Harlow joined the Department of Physics in 2017 following postdocs at Princeton University and Harvard University. He obtained a BA in physics and mathematics from Columbia University in 2006 and a PhD in physics from Stanford University in 2012. He is also a researcher in the Center for Theoretical Physics.

A biophysicist, Gene-Wei Li studies how bacteria optimize the levels of proteins they produce at both mechanistic and systems levels. His lab focuses on design principles of transcription, translation, and RNA maturation. Li joined the Department of Biology in 2015 after completing a postdoc at the University of California at San Francisco. He earned an BS in physics from National Tsinghua University in 2004 and a PhD in physics from Harvard University in 2010.

Michael McDonald focuses on the evolution of galaxies and clusters of galaxies, and the role that environment plays in dictating this evolution. This research involves the discovery and study of the most distant assemblies of galaxies alongside analyses of the complex interplay between gas, galaxies, and black holes in the closest, most massive systems. McDonald joined the Department of Physics and the Kavli Institute for Astrophysics and Space Research in 2015 after three years as a Hubble Fellow, also at MIT. He obtained his BS and MS degrees in physics at Queens University, and his PhD in astronomy at the University of Maryland in College Park.

Gabriela Schlau-Cohen combines tools from chemistry, optics, biology, and microscopy to develop new approaches to probe dynamics. Her group focuses on dynamics in membrane proteins, particularly photosynthetic light-harvesting systems that are of interest for sustainable energy applications. Following a postdoc at Stanford University, Schlau-Cohen joined the Department of Chemistry faculty in 2015. She earned a bachelors degree in chemical physics from Brown University in 2003 followed by a PhD in chemistry at the University of California at Berkeley.

Phiala Shanahans research interests are focused around theoretical nuclear and particle physics. In particular, she works to understand the structure and interactions of hadrons and nuclei from the fundamental degrees of freedom encoded in the Standard Model of particle physics. After a postdoc at MIT and a joint position as an assistant professor at the College of William and Mary and senior staff scientist at the Thomas Jefferson National Accelerator Facility, Shanahan returned to the Department of Physics as faculty in 2018. She obtained her BS from the University of Adelaide in 2012 and her PhD, also from the University of Adelaide, in 2015.

Omer Yilmaz explores the impact of dietary interventions on stem cells, the immune system, and cancer within the intestine. By better understanding how intestinal stem cells adapt to diverse diets, his group hopes to identify and develop new strategies that prevent and reduce the growth of cancers involving the intestinal tract. Yilmaz joined the Department of Biology in 2014 and is now also a member of Koch Institute for Integrative Cancer Research. After receiving his BS from the University of Michigan in 1999 and his PhD and MD from University of Michigan Medical School in 2008, he was a resident in anatomic pathology at Massachusetts General Hospital and Harvard Medical School until 2013.

In 2023, five MIT faculty were granted tenure in the School of Science:

Physicist Riccardo Comin explores the novel phases of matter that can be found in electronic solids with strong interactions, also known as quantum materials. His group employs a combination of synthesis, scattering, and spectroscopy to obtain a comprehensive picture of these emergent phenomena, including superconductivity, (anti)ferromagnetism, spin-density-waves, charge order, ferroelectricity, and orbital order. Comin joined the Department of Physics in 2016 after postdoctoral work at the University of Toronto. He completed his undergraduate studies at the Universita degli Studi di Trieste in Italy, where he also obtained a MS in physics in 2009. Later, he pursued doctoral studies at the University of British Columbia, Canada, earning a PhD in 2013.

Netta Engelhardt researches the dynamics of black holes in quantum gravity and uses holography to study the interplay between gravity and quantum information. Her primary focus is on the black hole information paradox, that black holes seem to be destroying information that, according to quantum physics, cannot be destroyed. Engelhardt was a postdoc at Princeton University and a member of the Princeton Gravity Initiative prior to joining the Department of Physics in 2019. She received her BS in physics and mathematics from Brandeis University and her PhD in physics from the University of California at Santa Barbara. Engelhardt is a researcher in the Center for Theoretical Physics and the Black Hole Initiative at Harvard University.

Mark Harnett studies how the biophysical features of individual neurons endow neural circuits with the ability to process information and perform the complex computations that underlie behavior. As part of this work, his lab was the first to describe the physiological properties of human dendrites. He joined the Department of Brain and Cognitive Sciences and the McGovern Institute for Brain Research in 2015. Prior, he was a postdoc at the Howard Hughes Medical Institutes Janelia Research Campus. He received his BA in biology from Reed College in Portland, Oregon and his PhD in neuroscience from the University of Texas at Austin.

Or Hen investigates quantum chromodynamic effects in the nuclear medium and the interplay between partonic and nucleonic degrees of freedom in nuclei. Specifically, Hen utilizes high-energy scattering of electron, neutrino, photon, proton and ion off atomic nuclei to study short-range correlations: temporal fluctuations of high-density, high-momentum, nucleon clusters in nuclei with important implications for nuclear, particle, atomic, and astrophysics. Hen was an MIT Pappalardo Fellow in the Department of Physics from 2015 to 2017 before joining the faculty in 2017. He received his undergraduate degree in physics and computer engineering from the Hebrew University and earned his PhD in experimental physics at Tel Aviv University.

Sebastian Lourido is interested in learning about the vulnerabilities of parasites in order to develop treatments for infectious diseases and expand our understanding of eukaryotic diversity. His lab studies many important human pathogens, including Toxoplasma gondii, to model features conserved throughout the phylum. Lourido was a Whitehead Fellow at the Whitehead Institute for Biomedical Research until 2017, when he joined the Department of Biology and became a Whitehead Member. He earned his BS from Tulane University in 2004 and his PhD from Washington University in St. Louis in 2012.

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Fourteen MIT School of Science professors receive tenure for 2022 ... - MIT News