Category Archives: Quantum Physics
Cormac McCarthy’s long-held admiration for Jewish achievement … – Jewish Insider
When Cormac McCarthy published his final two novels in quick succession late last year, it did not go unnoticed that he had created his first major female protagonist: Alicia Western, the tortured mathematical genius at the center of Stella Maris a hauntingly rendered transcription of her therapy sessions at a psychiatric institution in rural Wisconsin.
In form and focus, the book was an unusual departure for McCarthy, a titan of American literature who died two weeks ago, just short of his 90th birthday. His best-known protagonists had long been recognized as almost mythic avatars of a certain kind of masculine stoicism embodied by Alicias brother, Bobby, a laconic salvage diver whose story is told in a companion novel, The Passenger, which is more conventionally structured.
Equally intriguing, however, was that McCarthy had made the siblings Jewish. It was a curious biographical choice that has continued to puzzle McCarthy scholars who have scoured the books for insights into his decision. The most reasonable explanation, it seems, is that McCarthy was motivated, at least in part, by a commitment to historical reconstruction: The siblings father, a brilliant physicist who studied with Einstein, worked on the Manhattan Project, where a number of Jewish scientists helped design the atom bomb.
The Westerns are tormented by their connection to the project and the destruction it ultimately wrought. Bobby, for instance, fully understood that he owed his existence to Adolf Hitler, McCarthy writes in a characteristically portentous passage. That the forces of history which had ushered his troubled life into the tapestry were those of Auschwitz and Hiroshima, the sister events that sealed forever the fate of the West.
Aside from such musings, though, the topic of Jewish identity is hardly explored in the novels, where McCarthy more notably demonstrates his conceptual understanding of physics in a series of abstruse disquisitions. I tried very hard to find Yiddishkeit somewhere in there, Rick Wallach, the founder of the Cormac McCarthy Society, said in an interview with Jewish Insider not long after the novels had been published. I dont see it.
But the Westerns Jewish heritage was likely more meaningful to McCarthy than his own renderings might suggest. In some ways, it could be interpreted as a testament to a privately held and little-known reverence for the Jewish experience. The author had a sincere pattern of admiration for Jewish people and Jewish culture, said Bryan Giemza, an associate professor of humanities and literature at Texas Texas Tech University and the author of Science and Literature in Cormac McCarthys Expanding Worlds, published earlier this month.
Giemzas knowledge of McCarthys personal sentiments, he said, is based on conversations with people close to the author, who was famously guarded. He holds Jewish people in great esteem, Giemza confirmed to JI before McCarthys death.
That esteem was cemented in large part by McCarthys affiliation with the Santa Fe Institute, a nonprofit theoretical research center founded in 1984. McCarthy, who was raised in an Irish Catholic family in Tennessee, had no ancestral connection to Judaism. But he spent the last decades of his life surrounded by some of the worlds most accomplished Jewish physicists who were involved with the institute, where he was a longtime trustee.
It was there that he wrote his post-apocalyptic novel The Road, which won a Pulitzer Prize. His engagement, however, wasnt limited exclusively to literary production. McCarthy could also hold his own in regular conversations about math and science over tea with the institutes members, including its late co-founder Murray Gell-Mann, the Nobel Prize-winning particle physicist who became a close friend. Nearly all of the institutes eight founders, meanwhile, had worked on the Manhattan Project at Los Alamos in New Mexico where the fictional Westerns father also served.
Geoffrey West, a British-born physicist and a researcher at the institute, said he wasnt surprised when he learned that McCarthy had written a pair of Jewish characters who are prodigious at mathematics. Most of the people he admired as scientists were Jews, and its very natural to make one of these people or two of these people Jewish, he reasoned. The decidedly un-Jewish surname is strange, he acknowledged, even if it bears a resemblance to his own. But nevertheless.
West, a former president of the Santa Fe Institute who grew up in an Orthodox Jewish household, said he never asked McCarthy why he had given his characters Jewish backgrounds. They only talked a teeny bit about the books and not in any great detail, he said. McCarthy, who rarely engaged with the press, never publicly addressed the matter. His publisher, Alfred A. Knopf, declined multiple interview requests from JI before his death.
In lieu of a deeper answer, then, readers are left with the books themselves, which offer only a limited number of clues. In one particularly notable passage from Stella Maris, however, Alicia provides a key insight into her own relationship to Judaism when she is asked by her Jewish psychiatrist, Dr. Robert Cohen, if she has any Jewish family connections. No, she says, adding that she and her brother didnt grow up Jewish.
But you knew you were Jewish, Dr. Cohen responds flatly.
No. I knew something, Alicia, who has checked herself into the psychiatric ward after experiencing hallucinations, says somewhat puzzlingly, before arriving at her central observation. Anyway, my forebears counting coppers out of a clackdish are what have brought me to this station in life, she continues. Jews represent two percent of the population and eighty percent of the mathematicians. If those numbers were even a little more skewed wed be talking about a separate species.
If Alicia is aware that her assessment is farfetched, as Dr. Cohen diplomatically suggests, she does not seem to care. It isnt fetched far enough, she claims, even while recognizing that there are limitations to explaining her theory. Darwins question remains unanswered. How do we come by mental abilities that have no history? she wonders, adding, How does making change in the market prepare ones grandchildren for quantum mechanics? For topology?
McCarthy had long been fascinated by coins and currency, a recurring symbol across his novels, but Alicias belief in a kind of heritable Ashkenazi intelligence seems largely unrelated to that fixation. If Im not mistaken, thats lifted straight from The Bell Curve, which of course has been pilloried, for good reason, Giemza, the McCarthy expert, told JI, referring to a long-discredited book that posits a direct connection between race and intelligence. Its never good when you get into genetic essentialism.
In an interview, Giemza confessed that he was a little surprised and somewhat disappointed to find the passage, even as he acknowledged that Alicia is floating a theory that a lot of people would probably be inclined to believe. If you look at people of McCarthys generation, kind of Anglo-Americans, there is the notion among some that Gods chosen people applies to intellect and ability, he told JI.
Still, he made sure to clarify that he was not attributing such thinking to McCarthy himself, anticipating that some critics might be tempted to generalize about Jewishness as the common theme to explain McCarthys friendships with scientists an idea he views as misguided. But he questioned McCarthys reason for including the passage at all. Its kind of like, well, to what end? he wondered. What does it serve?
It was not the first instance in which McCarthy had suggested a link between Jewish heritage and mental acuity. In his 1992 novel All the Pretty Horses, the first installment in his popular Border Trilogy, one character recounts, in prophetic detail, the colonial history that led her ancestors to Mexico. There had always been a rumor that they were of jewish extraction, McCarthy writes, lowercase his. Possibly its true. They were all very intelligent. Certainly theirs seemed to me at least to be a jewish destiny. A latterday diaspora. Martyrdom. Persecution. Exile.
McCarthys decision to lowercase jew was in keeping with his idiosyncratic aversion to standard grammatical conventions he also eschewed quotation marks, for example. He had opted for the same usage in Blood Meridian, an anti-western that is widely viewed as his finest novel, while referring to a Prussian jew named Speyer, who is among just a handful minor Jewish characters McCarthy would write into his novels until he gave them central roles in his last two works where all Jewish references are capitalized.
While it is unclear when exactly McCarthy decided that he would make the Westerns Jewish, early drafts of The Passenger, which he began writing decades ago, indicate that it was not his original plan. Lydia Cooper, a professor of American literature at Creighton University in Omaha, has reviewed McCarthys drafts written roughly between 2000 and 2004, which were recently made publicly available in an archive held at Texas State University.
I didnt see anything in those drafts that gave any indication the Western siblings are Jewish, and several minor indications theyre not, she told JI, noting that there are references to Bobby being educated by nuns. In another draft, according to Cooper, we are told that Bobby Westerns father had married before and not told their mother that hed been married previously because his first wife was Catholic. That line mostly echoes the published text, with one notable exception: Their fathers first wife became an Orthodox Jew.
No obvious reason is given to explain why the Westerns father would hesitate to reveal to his second wife that he had been married to an Orthodox Jewish woman. But Cooper suggested that might be beside the point. McCarthy didnt just shift the main characters to being Jewish, she said, but he was intentional about it, to a certain extent.
From a biological standpoint, it doesnt matter that the siblings fathers first wife was Jewish rather than Catholic, but it creates a bit more context for the fathers backstory, Cooper elaborated. If I had to describe it, it feels to me like McCarthy decided his protagonists needed to be Jewish, and he transposed their identities, like a musician shifting the same melody to a different key.
Notably, she said, most of the lengthy sections on physics from both novels arent in the papers she reviewed. The absence of such material, she observed, suggests that McCarthy had likely begun to depict his characters as Jewish around the time that he really started delving into the physics.
Meanwhile, Giemza said he had learned that Alicia is modeled, in part, on a woman who had been a visitor at the Santa Fe Institute but is not, to his awareness, of Jewish ancestry. The Jewish element, he speculated in an email to JI, seems to be a kind of artistic imposition, to what end, we will long be musing.
In a new paper recently presented at an online salon hosted by the Southwest Popular/American Culture Association, Wallach, the Cormac McCarthy Society founder, seeks to examine how the Westerns Judaism functions in a manner that is more significant than a historical referent to what he calls the Los Alamos ethnic mix.
As we can see, the most apparent signification is its resonances with the age-old theme of persecution and exile, he writes of Bobby in particular, who is pursued by threateningly anonymous agents after he finds that a body is missing from a sunken jet during a salvage dive off the coast of New Orleans. Stripped of his worldly goods and threatened with likely imprisonment, Bobby is forced to flee, a wandering Jew set on an aimless retreat through heartland America and ultimately driven abroad to a sanctuary in Spain.
Bobbys persecution by this nameless, faceless government, Wallach said in an interview with JI, is reminiscent of what he characterized as a kind of Kafkaesque nightmare.
But like most of McCarthys books, it is far easier to discern Catholic influences rather than Jewish themes. Perhaps most notably, The Passenger opens with Alicias suicide, her lifeless body found hanging among the bare gray poles of the winter trees on a cold and barely spoken Christmas day. It concludes during Holy Week in Ibiza, where McCarthy finished his second novel, Outer Dark, in the 1960s.
That book, set in the Appalachian South around the turn of the 20th century, features what is likely the first overt Jewish reference in McCarthys oeuvre. Its a humorous exchange in which one character asks guilelessly, Whats a jew? The answer, delivered by an amiable hog herder, is that a Jew is one of them old-timey people from in the bible.
Among the most meaningful demonstrations of McCarthys understanding of Judaism comes from an unexpected source: His screenplay for The Counselor, a 2013 crime thriller directed by Ridley Scott. In one scene, an unnamed Jewish diamond dealer unspools an oracular description of what he regards as the unique fate of the Jewish people. There is no culture save the Semitic culture. There, the dealer begins. The last known culture before that was the Greek and there will be no culture after. Nothing.
Speaking to the titular counselor, he goes on to argue that the heart of any culture is to be found in the nature of the hero, adding: Who is that man who is revered? In the western world it is the man of God. From Moses to Christ. The prophet. The penitent. Such a figure is unknown to the Greeks. Unheard of. Unimaginable. Because you can only have a man of God, not a man of gods. And this God is the God of the Jewish people. There is no other god. We see the figure of him what is the word? Purloined. Purloined in the West.
How do you steal a God? He is immovable, the dealer concludes. The Jew beholds his tormentor dressed in the vestments of his own ancient culture. Everything bears a strange familiarity. But the fit is always poor and the hands are always bloody.
To Giemza, McCarthys assessment, told through the dealer, is pretty darn interesting, he said. Here, he shows an awareness of all the trauma of Jewish history and displacement, he told JI. But more, he seems to suggest that, for example, American sort of WASPy culture whatever the American mold is for any kind of Anglo-American Protestant identity is itself a type of theft. That Christianity is little more than a secondhand elaboration on Judaism.
Im not going to ascribe this to McCarthy, but I suspect that this is him, Giemza said. I think we get an insight into perhaps his understanding of Jewish identity and history.
McCarthys reverence for abstract mathematical concepts was, perhaps, intertwined with that understanding not least with respect to Alicia. Some of my colleagues have asked this question: Do you think the almost mystical way she talks about mathematics has any kind of relation to her thoughts about Jewishness or just religion in general? Stacey Peebles, an associate professor of English at Centre College in Kentucky and the president of the Cormac McCarthy Society, said in an interview with JI. Theres probably something to be said for that, because the way she talks about math is almost like a divine presence.
What does it mean to think about something that is so separate from the world we actually inhabit and that you cant visualize? Peebles mused. I mean, it starts to sound like God at a certain level or, at the very least, some kind of expression of faith.
Relatedly, West, a theoretical physicist who thinks in grand abstractions, said he has long pondered why so many Jewish scientists have been drawn, in a manner of speaking, to a discipline that involves no less a task than decoding the universe. That, I have speculated, is because of the stubborn Jewish determinism that theres one God, he told JI. Thats it. One God, which has permeated Jewish thinking from biblical times.
Somehow, that got morphed or evolved into the search for everything is unified, and so its not surprising that Jews would end up being at the forefront of trying to understand grand unified theories of the elementary particles and the origins of the universe, he explained. Even though most of us are secular, deep down in our archetypal subconscious, there remains this one God kind of concept.
There is little reason to doubt that McCarthy, a stubborn outsider himself who felt most at home in the company of scientists, would find something to admire in that theory.
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Cormac McCarthy's long-held admiration for Jewish achievement ... - Jewish Insider
DNA has revealed the origin of this giant ‘mystery’ gecko – Science News Magazine
A lizard called Delcourts giant gecko has long been one of herpetologys biggest mysteries literally.
Presumed extinct, the animal is by far the largest gecko known to have crawled the Earth, measuring at least 600 millimeters, or about two feet, from snout to tail tip. The only example scientists have of the gecko, however, is a single museum specimen, preserved in the 19th century with no notes as to its origin or identity.
Now, DNA from the specimen reveals that the colossal lizard belongs to a group of New Caledonian diplodactylid geckos, researchers report June 19 in Scientific Reports. Geckos in this lineage repeatedly evolved extreme body sizes on the archipelago east of Australia.
Compared to all other geckos, its monstrous, says Matthew Heinicke, an evolutionary biologist at the University of Michigan-Dearborn. It happens to be in a lineage where evolution of gigantism wasnt a one-off event.
Previously dubbed Hoplodactylus delcourti, the gecko was renamed Gigarcanum delcourti in the new study, placing the animal in its own genus whose name means giant mystery. It is about 50 percent as long and several times as heavy as the largest living gecko species (Rhacodactylus leachianus), also a member of the New Caledonian group.
Likely a nocturnal hunter, G. delcourti was big enough to prey on birds and lizards, including other geckos. Its toe pads and long claws suggest it lived in trees, though it was probably the maximum size at which a geckocould still adhere to vertical surfaces with its hallmark sticky grip, Heinicke says.
The gecko came to scientists attention in the 1980s after collections manager Alain Delcourt found the long-forgotten specimen at the Natural History Museum of Marseille in France. Stuffed rather than stored in spirits, the gecko sports a thick trunk, bulbous head and brown skin with faint red bands. Herpetologist Aaron Bauer of Villanova University in Pennsylvania was a graduate student when he arrived at the museum in 1983 to investigate the newly rediscovered specimen.
When Delcourt removed the enormous gecko from a cabinet, my jaw dropped, Bauer says.
Bauer cowrote the first description of the species in 1986, placing the reptile with a New Zealand gecko group based on itsphysical characteristics. He also suggested that because of its coloring and size, the gecko could be the kawekaweau a huge arboreal lizard from the folklore of the Indigenous Mori people.
Since then, techniques for retrieving and analyzing archival DNA have accelerated, allowing scientists to glean new information from degraded museum specimens, including of extinct species such as the dodo and thylacine, also known as the Tasmanian tiger (SN: 5/19/08).
Heinicke, Bauer and colleagues revisited the mysterious giant gecko, extracting and analyzing DNA from one of its femurs. That genetic material rewrote G. delcourtis origin story, showing that it is not even closely related to New Zealands geckos. The diplodactylid geckos of New Caledonia and New Zealand are separated by about 45 million years of evolution.
The teams finding turns things on their head, as gecko geeks worldwide have long associated G. delcourti with New Zealand, says Paul Doughty, a herpetologist at the Western Australian Museum in Perth. But this is the thing about these precious museum specimens. With new technology, they can give up new secrets.
Not everyone is surprised by the finding. Trevor Worthy, a paleontologist at Flinders University in Adelaide, Australia, previously suggested that G. delcourti may have come from New Caledonia, given its absence in New Zealands extensive fossil record. You would think that such a big animal would have turned up, and there was no sign of it, Worthy says. Its exciting to see this mystery cleared up.
Could G. delcourti still be nestled in the treetops of New Caledonia?
Its unlikely, but possible, the researchers say. New geckos continue to be discovered on the islands. Id like to hold out at least a tiny glimmer of hope that there could be something out there, Bauer says.
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DNA has revealed the origin of this giant 'mystery' gecko - Science News Magazine
In a first, JWST detected starlight from distant galaxies with quasars – Science News Magazine
CAMBRIDGE, MASS. For the first time, astronomers have detected starlight from distant galaxies that host extremely bright supermassive black holes called quasars.
Data from the James Webb Space Telescope reveal that four of these galaxies are massive, compact and possibly disk-shaped, astronomers report June 12 at the JWST First Light meeting. Studying the galaxies could help solve the mystery of how black holes in the early universe grew so big so fast (SN: 1/18/21).
Ever since the discovery of [distant] quasars, there have been studies trying to detect their host galaxies, said MIT astrophysicist Minghao Yue. But until JWSTs sharp infrared eyes came along, it wasnt possible. This opens up brand new windows towards finally understanding luminous quasars and their host galaxies.
Quasars are black holes that are feeding so furiously, the material they gobble heats to white-hot temperatures, shining brighter than the stars in the galaxy around them. Theyre so bright and distant that each appears as a single, starlike point of light.
Two independent groups used that starlike quality to erase the black hole glow from images of their galaxies, like a sculptor coaxing a figure out of marble.
Yue and colleagues used JWST to observe six quasar-hosting galaxies. Around the same time, astrophysicist Xuheng Ding of the Kavli Institute for the Physics and Mathematics of the Universe in Tokyo and colleagues used JWST to look at another pair of quasars. The light from all the quasars was emitted more than 12.8 billion years ago, or less than a billion years after the Big Bang.
The teams used actual stars in the images to simulate the starlike shapes of the quasars. Then they subtracted the simulated quasar from the image of each whole galaxy, and voil: Only starlight remained.
Dings team got a direct peek at both of their galaxies, while Yues team glimpsed two of their six. All the measured galaxies appear to be less than a tenth as wide as the Milky Way, measuring between 2,600 and 8,000 light-years across. The two galaxies that Yue and colleagues observed contain enough stars to make up between 10 billion and 100 billion times the mass of the sun, the researchers estimate. The pair that Ding and colleagues looked at weigh in at about 25 billion and 63 billion solar masses, the team reported at the meeting and in a study to appear in Nature.
Those masses are comparable to that of all the stars in the Milky Way, which in total add up to roughly 60 billion times the mass of the sun. Thats surprisingly massive for so early in the universes history.
Whats more, the galaxies seem to break a rule set by observations of galaxies in the nearby universe. Locally, galaxies tend to split their mass between stars and black holes in a predictable way: The more massive its central supermassive black hole, the more stars a galaxy has. These galaxies appear to pack more mass into their black hole than their amount of stars should allow.
At least for these luminous quasars, they really are over-massive, Yue said.
The mass calculations might prove to be overestimates, says astrophysicist Paul Shapiro of the University of Texas at Austin who was not involved in either study. Converting the light that JWST can see into stars rests on assumptions about how many stars of various masses a galaxy has. Modern galaxies have a lot more dim, lightweight stars than bright, hefty ones, so astronomers typically assume that the brightest stars they see are just the tip of the iceberg. But that might not have been the case 800 million years after the Big Bang, Shapiro says.
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Youre observing the tail and inferring the dog, he says. If there were a mass distribution that favors high-mass stars, you could be significantly overestimating the mass associated with the light.
But the fact that we can see it at all is very exciting, says astronomer Madeline Marshall of the National Research Council Canada in Victoria. The fact that two groups are reporting starlight from quasar hosts independently is very convincing, she says.
Pre-JWST, we could not detect host galaxies of [distant] quasars, she said at the meeting. Now, with only the first year of observations we can actually detect some of these hosts for the first time.
These first few quasar hosts are just the beginning, Ding says. JWST is scheduled to observe at least 10 more, some of which are even farther away. A larger sample will help astronomers figure out enduring cosmic riddles about how black holes and galaxies influence each other as they grow.
We dont know how black holes can be so big in the early universe, Ding says. You need to understand the environment of this monster, how it can collect so much matter to it. So knowing the conditions the mass of the host galaxies, for example at least then you can say how their local environment is.
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In a first, JWST detected starlight from distant galaxies with quasars - Science News Magazine
Quantum oscillations in field-induced correlated insulators of a moir superlattice – EurekAlert
image:(a) Phase diagrams of half-filling states as a function of displacement field and magnetic field. Here VP is the valley-polarized state, IVC is the intervalley coherence state, BZO are the Brown-Zak oscillations. (b) Quantum oscillations of resistance. view more
Credit: Science China Press
Graphene based moir superlattice, stacked by two pieces of single or multilayer graphene with a twisted angle, is famous for hosting moir flat bands and correlated states. Thus far, a new field of twistronics has emerged and attracted lots of attentions from various fields including materials science, theory, electronics and optoelectronics, and etc., since the discovery of the correlated insulators and superconductivity in twisted bilayer graphene (1+1). Compared to the 1+1 system, the band structure in twisted double bilayer graphene (2+2) can be further tuned by electric field, aside from the twisted angle, and thus it allows a tuning of flat bands and the correlation strength in situ. Recently, the spin-polarized and valley polarized correlated insulators have been observed when the moir bands are half filled in 2+2. With its highly tunable nature, 2+2 offers a new platform for discovering novel exotic phases in the correlated insulating states.
Recently, a team led by Dr. Wei Yang and Dr. Guangyu Zhang (Institute of Physics, Chinese Academy of Sciences) reports the observation of anomalous quantum oscillations (QOs) of correlated insulators in twisted double bilayer graphene. The team has long been devoted to explore the quantum transport behaviors in moir superlattices. Previously, they found that new correlated insulators with valley polarizations emerges at half fillings of energy bands, thanks to the orbital Zeeman effect in perpendicular magnetic field. To their surprise, recently, they found that the resistance of correlated insulators in 2+2 oscillates periodically with the inverse of magnetic field, similar to the Shubnikov de Haas oscillations in metal. Moreover, the oscillating periodicity of the insulating states is found tunable by electric field. To account for these anomalous phenomena, they built a phenomenological inverted band model. With the parameters extracted from experiments, calculations of the density of states from the model qualitatively reproduce the electric field tunable QOs of correlated insulators. The observation of QOs of insulators in this study builds an intimate connection to other strong correlated systems like Kondo insulators, topological insulators and excitonic insulators, and it highly suggests that more exotic phases are to be discovered in this system.
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Quantum oscillations in field-induced correlated insulators of a moir superlattice
https://doi.org/10.1016/j.scib.2023.05.006
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Quantum oscillations in field-induced correlated insulators of a moir superlattice - EurekAlert
First Measurement of Electron Spin in Kagome Quantum Materials – SciTechDaily
For the first time, an international research team has measured the electron spin in a new class of quantum materials called kagome materials, potentially transforming how quantum materials are studied. This advancement could pave the way for developments in fields like renewable energy, biomedicine, electronics, and quantum computing.
An international research team has succeeded for the first time in measuring the electron spin in matter i.e., the curvature of space in which electrons live and move within kagome materials, a new class of quantum materials.
The results obtained published in the journal Nature Physics could revolutionize the way quantum materials are studied in the future, opening the door to new developments in quantum technologies, with possible applications in a variety of technological fields, from renewable energy to biomedicine, from electronics to quantum computers.
Success was achieved by an international collaboration of scientists, in which Domenico Di Sante, professor at the Department of Physics and Astronomy Augusto Righi, participated for the University of Bologna as part of his Marie Curie BITMAP research project. He was joined by colleagues from CNR-IOM Trieste, Ca Foscari University of Venice, University of Milan, University of Wrzburg (Germany), University of St. Andrews (UK), Boston College, and University of California, Santa Barbara (USA).
Through advanced experimental techniques, using light generated by a particle accelerator, the Synchrotron, and thanks to modern techniques for modeling the behavior of matter, the scholars were able to measure electron spin for the first time, related to the concept of topology.
Three perspectives of the surface on which the electrons move. On the left, the experimental result, in the center and on the right the theoretical modeling. The red and blue colors represent a measure of the speed of the electrons. Both theory and experiment reflect the symmetry of the crystal, very similar to the texture of traditional Japanese kagome baskets. Credit: University of Bologna
If we take two objects such as a football and a doughnut, we notice that their specific shapes determine different topological properties, for example, because the doughnut has a hole, while the football does not, Domenico Di Sante explains. Similarly, the behavior of electrons in materials is influenced by certain quantum properties that determine their spinning in the matter in which they are found, similar to how the trajectory of light in the universe is modified by the presence of stars, black holes, dark matter, and dark energy, which bend time and space.
Although this characteristic of electrons has been known for many years, no one had until now been able to measure this topological spin directly. To achieve this, the researchers exploited a particular effect known as circular dichroism: a special experimental technique that can only be used with a synchrotron source, which exploits the ability of materials to absorb light differently depending on their polarization.
Scholars have especially focused on kagome materials, a class of quantum materials that owe their name to their resemblance to the weave of interwoven bamboo threads that make up a traditional Japanese basket (called, indeed, kagome). These materials are revolutionizing quantum physics, and the results obtained could help us learn more about their special magnetic, topological, and superconducting properties.
These important results were possible thanks to a strong synergy between experimental practice and theoretical analysis, adds Di Sante. The teams theoretical researchers employed sophisticated quantum simulations, only possible with the use of powerful supercomputers, and in this way guided their experimental colleagues to the specific area of the material where the circular dichroism effect could be measured.
Reference: Flat band separation and robust spin Berry curvature in bilayer kagome metals by Domenico Di Sante, Chiara Bigi, Philipp Eck, Stefan Enzner, Armando Consiglio, Ganesh Pokharel, Pietro Carrara, Pasquale Orgiani, Vincent Polewczyk, Jun Fujii, Phil D. C. King, Ivana Vobornik, Giorgio Rossi, Ilija Zeljkovic, Stephen D. Wilson, Ronny Thomale, Giorgio Sangiovanni, Giancarlo Panaccione and Federico Mazzola, 18 May 2023, Nature Physics.DOI: 10.1038/s41567-023-02053-z
The first author of the study is Domenico Di Sante, a researcher at the Augusto Righi Department of Physics and Astronomy of the University of Bologna. He worked with scholars from the CNR-IOM of Trieste, the Ca Foscari University of Venice, the University of Milan, the University of Wrzburg (Germany), the University of St. Andrews (UK), the Boston College and the University of Santa Barbara (USA).
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First Measurement of Electron Spin in Kagome Quantum Materials - SciTechDaily
Physicists split bits of sound using quantum mechanics – Science News Magazine
You cant divide the indivisible, unless you use quantum mechanics. Physicists have now turned to quantum effects to split phonons, the smallest bits of sound, researchers report in the June 9 Science.
Its a breakthrough that mirrors the sort of quantum weirdness thats typically demonstrated with light or tiny particles like electrons and atoms (SN: 7/27/22). The achievement may one day lead to sound-based versions of quantum computers or extremely sensitive measuring devices. For now, it shows that mind-bending quantum weirdness applies to sound as well as it does to light.
There was no one that had really explored that, says engineering physicist Andrew Cleland of the University of Chicago. Doing so allows researchers to draw parallels between sound waves and light.
Phonons have much in common with photons, the tiniest chunks of light. Turning down the volume of a sound is the same as dialing back the number of phonons, much like dimming a light reduces the number of photons. The very quietest sounds of all consist of individual and indivisible phonons.
Unlike photons, which can travel through empty space, phonons need a medium such as air or water or in the case of the new study, the surface of an elastic material. Whats really kind of, in my mind, amazing about that is that these sound waves [carry] a very, very small amount of energy, because its a single quantum, Cleland says. But it involves the motion of a quadrillion atoms that are all working together to [transmit] this sound wave.
Phonons cant be permanently broken into smaller bits. But, as the new experiment showed, they can be temporarily divided into parts using quantum mechanics.
Cleland and his team managed the feat with an acoustic beam splitter, a device that allows about half of an impinging torrent of phonons to pass through while the rest get reflected back. But when just one phonon at a time meets the beam splitter, that phonon enters a special quantum state where it goes both ways at once. The simultaneously reflected and transmitted phonon interacts with itself, in a process known as interference, to change where it ultimately ends up.
The lab demonstration of the effect relied on sound millions of times higher in pitch than humans can hear, in a device cooled to temperatures very near absolute zero. Instead of speakers and microphones to create and hear the sound, the team used qubits, which store quantum bits of information (SN: 2/9/21). The researchers launched a phonon from one qubit toward another qubit. Along the way, the phonon encountered a beam splitter.
Adjusting the parameters of the setup modified the way that the reflected and transmitted portions of the phonon interacted with each other. That allowed the researchers to quantum mechanically change the odds of the whole phonon turning up back at the qubit that launched the phonon or at the qubit on the other side of the beam splitter.
A second experiment confirmed the quantum mechanical behavior of the phonons by sending phonons from two qubits to a beam splitter between them. On their own, each phonon could end up back at the qubit it came from or at the one on the opposite side of the beam splitter.
If the phonons were timed to arrive at the beam splitter at the exact same time, though, they travel together to their ultimate destination. That is, they still unpredictably go to one qubit or the other, but they always end up at the same qubit when the two phonons hit the beam splitter simultaneously.
If phonons followed the classical, nonquantum rules for sound, then there would be no correlation in where the two phonons go after hitting the beam splitter. The effect could serve as the basis for fundamental building blocks in quantum computers known as gates.
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The next logical step in this experiment is to demonstrate that we can do a quantum gate with phonons, Cleland says. That would be one gate in the assembly of gates that you need to do an actual computation.
Sound-based devices are not likely to outperform quantum computers that use photons (SN: 2/14/18). But phonons could lead to new quantum applications, says Andrew Armour, a physicist at the University of Nottingham in England who was not involved in the study.
Its probably not so clear what those [applications] are at the moment, Armour says. What youre doing is extending the [quantum] toolbox. People will build on it, and it will keep going, and theres no sign of it stopping any time soon.
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Physicists split bits of sound using quantum mechanics - Science News Magazine
New Discovery: Merging Twistronics and Spintronics May … – Newswise
Newswise Twistronics isnt a new dance move, exercise equipment, or new music fad. No, its much cooler than any of that. It is an exciting new development in quantum physics and material science where van der Waals materials are stacked on top of each other in layers, like sheets of paper in a ream that can easily twist and rotate while remaining flat, and quantum physicists have used these stacks to discover intriguing quantum phenomena.
Adding the concept of quantum spin with twisted double bilayers of an antiferromagnet, it is possible to have tunable moir magnetism. This suggests a new class of material platform for the next step in twistronics: spintronics. This new science could lead to promising memory and spin-logic devices, opening the world of physics up to a whole new avenue with spintronic applications.
A team of quantum physics and materials researchers at Purdue University has introduced the twist to control the spin degree of freedom, using CrI3, an interlayer-antiferromagnetic-coupled van der Waals (vdW) material, as their medium. They have published their findings, Electrically tunable moir magnetism in twisted double bilayers of chromium triiodide, inNature Electronics.
In this study, we fabricated twisted double bilayer CrI3, that is, bilayer plus bilayer with a twist angle between them, says Dr. Guanghui Cheng, co-lead author of the publication. We report moir magnetism with rich magnetic phases and significant tunability by the electrical method.
The team, mostly from Purdue, has two equal-contributing lead authors: Dr. Guanghui Cheng and Mohammad Mushfiqur Rahman. Cheng was a postdoc in Dr.Yong P. Chens group at Purdue University and is now an Assistant Professor in Advanced Institute for Material Research (AIMR, where Chen is also affiliated as a principal investigator) at Tohoku University. Mohammad Mushfiqur Rahman is a PhD student in Dr.Pramey Upadhyayas group. Both Chen and Upadhyaya are corresponding authors of this publication and are professors at Purdue University. Chen is the Karl Lark-Horovitz Professor of Physics and Astronomy, a Professor of Electrical and Computer Engineering, and the Director of Purdue Quantum Science and Engineering Institute. Upadhyaya is an Assistant Professor of Electrical and Computer Engineering. Other Purdue-affiliated team members include Andres Llacsahuanga Allcca (PhD student), Dr. Lina Liu (postdoc), and Dr. Lei Fu (postdoc) from Chens group, Dr. Avinash Rustagi (postdoc) from Upadhyayas group and Dr. Xingtao Liu (former research assistant at Birck Nanotechnology Center).
We stacked and twisted an antiferromagnet onto itself and voila got a ferromagnet, says Chen. This is also a striking example of the recently emerged area of twisted or moir magnetism in twisted 2D materials, where the twisting angle between the two layers gives a powerful tuning knob and changes the material property dramatically.
To fabricate twisted double bilayer CrI3, we tear up one part of bilayer CrI3, rotate and stack onto the other part, using the so-called tear-and-stack technique, explains Cheng. Through magneto-optical Kerr effect (MOKE) measurement, which is a sensitive tool to probe magnetic behavior down to a few atomic layers, we observed the coexistence of ferromagnetic and antiferromagnetic orders, which is the hallmark of moir magnetism, and further demonstrated voltage-assisted magnetic switching. Such a moir magnetism is a novel form of magnetism featuring spatially varying ferromagnetic and antiferromagnetic phases, alternating periodically according to the moir superlattice.
Twistronics up to this point have mainly focused on modulating electronic properties, such as twisted bilayer graphene. The Purdue team wanted to introduce the twist to spin degree of freedom and chose to use CrI3, an interlayer-antiferromagnetic-coupled vdW material. The result of stacked antiferromagnets twisting onto itself was made possible by having fabricated samples with different twisting angles. In other words, once fabricated, the twist angle of each device becomes fixed, and then MOKE measurements are performed.
Theoretical calculations for this experiment were performed by Upadhyaya and his team. This provided strong support for the observations arrived at by Chens team.
Our theoretical calculations have revealed a rich phase diagram with non-collinear phases of TA-1DW, TA-2DW, TS-2DW, TS-4DW, etc., says Upadhyaya.
This research folds into an ongoing research avenue by Chens team. This work follows several related recent publications by the team related to novel physics and properties of 2D magnets, such as Emergence of electric-field-tunable interfacial ferromagnetism in 2D antiferromagnet heterostructures, which was recently published in Nature Communications. This research avenue has exciting possibilities in the field of twistronics and spintronics.
The identified moir magnet suggests a new class of material platform for spintronics and magnetoelectronics, says Chen. The observed voltage-assisted magnetic switching and magnetoelectric effect may lead to promising memory and spin-logic devices. As a novel degree of freedom, the twist can be applicable to the vast range of homo/heterobilayers of vdW magnets, opening the opportunity to pursue new physics as well as spintronic applications.
This work is partially supported by US Department of Energy (DOE) Office of Science through the Quantum Science Center (QSC, a National Quantum Information Science Research Center) and Department of Defense (DOD) Multidisciplinary University Research Initiatives (MURI) program (FA9550-20-1-0322). Cheng and Chen also received partial support from WPI-AIMR, JSPS KAKENHI Basic Science A (18H03858), New Science (18H04473 and 20H04623), and Tohoku University FRiD program in early stages of the research. Upadhyaya also acknowledges support from the National Science Foundation (NSF) (ECCS-1810494). Bulk CrI3crystals are provided by the group of Zhiqiang Mao from Pennsylvania State University under the support of the US DOE (DE-SC0019068). Bulk hBN crystals are provided by Kenji Watanabe and Takashi Taniguchi from National Institute for Materials Science in Japan under support from the JSPS KAKENHI (Grant Numbers 20H00354, 21H05233 and 23H02052) and World Premier International Research Center Initiative (WPI), MEXT, Japan.
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New Discovery: Merging Twistronics and Spintronics May ... - Newswise
Microsoft reaches a key milestone in its quest to build a quantum … – GeekWire
This Microsoft illustration depicts a future quantum supercomputer operating in an Azure data center. (Microsoft Image)
Microsoft says it has achieved an important physics breakthrough representing the first milestone in its long-term initiative to build a quantum supercomputer capable of solving some of the worlds most difficult problems.
A peer-reviewed paper in Physical Review B, a journal of the American Physical Society, confirmed that the companys approach can create and control Majorana, a type of particle considered key to the future creation of scalable and stable qubits, the fundamental units of quantum information.
Its akin to inventing steel, leading to the launch of the Industrial Revolution, said Krysta Svore, Microsofts vice president of advanced quantum development, in a video outlining the companys quantum supercomputer roadmap.
Quantum computing uses the principles of quantum physics to process information in ways that traditional computers cant, potentially solving complex problems much more quickly. Unlike classical bits that can be either 0 or 1, qubits can exist in multiple states at once, allowing quantum computers to perform many calculations simultaneously.
Our goal is to compress the next 250 years of chemistry and material science progress into the next 25, Microsoft CEO Satya Nadella said in a video Wednesday introducing the companys quantum announcements.
Nadella as far back in 2017 was identifying quantum computing, virtual and augmented reality and artificial intelligence as the three technologies he believed at the time were most likely to shape the future.
Microsoft announced the milestone along with a new service called Azure Quantum Elements, which uses AI and high-performance computing to accelerate scientific research; and an AI-powered copilot for its Azure Quantum service, letting researchers use natural language for difficult chemistry and materials science problems.
The company is competing against several other major tech companies pursuing quantum breakthroughs, including IBM, Google, and Amazon, in addition to quantum companies and research institutions.
The announcements build on Microsofts existing momentum in quantum computing with commercial partners such as Johnson Matthey and government agencies including the Pentagons Defense Advanced Research Projects Agency.
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Microsoft reaches a key milestone in its quest to build a quantum ... - GeekWire
Creating superconducting circuits : News Center – University of Rochester
June 21, 2023
CIRCUIT MAKERS: Physics and astronomy professor Machiel Blok (middle) and PhD students (L-R) Ray Parker, Mihirangi Medahinne, Liz Champion, and Zihao Wang, in front of the dilution refrigerator in Bloks lab. The team fabricates superconducting circuits that can be used in a variety of applications such as quantum computing. (University of Rochester photo / J. Adam Fenster)
In the quest to unlock the power of quantum computers, scientists such as Machiel Blok study information processing at the infinitesimally small level of quantum mechanics.
Blok, an assistant professor in the Department of Physics and Astronomy at the University of Rochester, develops superconducting circuits, a type of electronic circuit that uses materials that have little to no electrical resistance when they are at very low temperatures. When currents flow through a typical conductor, such as copper, some of the energy is lost due to resistance. In a superconductor, however, there is zero resistance, meaning it can conduct electricity without any energy loss. This property emerges due to quantum mechanical effectsthe behavior of particles at the atomic and subatomic levels.
Blok is formulating new techniques to improve superconducting circuits and make quantum computers and simulators that may eventually solve problems that classical computers could never solve.
Quantum algorithms are extremely sensitive to noise, and a seemingly small disturbance can lead an operation to fail. We aim to design superconducting circuits that protect against noise in future quantum computers.
In quantum mechanics, particles can exist in multiple states at the same time, a phenomenon known as superposition. While a regular computer consists of billions of transistors called bits, quantum computers are based on qubits. Unlike ordinary transistors, which can be either 0 (off) or 1 (on), qubits are governed by the laws of quantum mechanics and can be both 0 and 1 at the same time. Superconducting circuits can create qubits, put them into superpositions of different states, and manipulate these superpositions.
By carefully controlling the interactions between these qubits, researchers can execute quantum algorithms, leading to much faster computing than that conducted by classical computers, Blok says.
Block recently received a Young Investigator Research Program award from the Air Force Office of Scientific Research for his work in quantum information sciences. His current research explores a new way to store and transfer quantum information more efficiently in superconducting circuits using qudits instead of qubits. A qudit-based processor goes beyond binary quantum logic (0 and 1) and allows building blocks to have three or more logical states (0, 1, 2, etc.) in which to encode information. Bloks method is based on using photonstiny packets of electromagnetic radiationto create and manipulate qudits to perform computations. The method could ultimately help protect quantum information from noiseunintended interactions between qudits and the environment.
Quantum algorithms are extremely sensitive to noise, and a seemingly small disturbance can lead an operation to fail, completely ruining a quantum computation, Blok says. We aim to design superconducting circuits that protect against noise in future quantum computers and to develop technology to make quantum computers more powerful and reliable.
Photos by University photographer J. Adam Fenster.
CHIP SHOT: Blok and the members of his lab create superconducting chips by patterning metals such as niobium or aluminum on silicon chips. They begin by fabricating a spiral resonator at the Integrated Nanosytems Center (URnano) in Goergen Hall on the River Campus in collaboration with John Nichol, an associate professor of physics. In a superconducting circuit, a spiral resonator is essentially a tightly wound wire coiled in a spiral-shaped pattern using the materialin this case, niobiumthat will take on superconducting properties when cooled down. The spiral resonator is like a tuning fork for the electrical signals; it helps to filter and control the flow of electrical signals in a precise and efficient manner by selectively responding to and amplifying certain frequencies while minimizing other frequencies.
COLD CASE: After the researchers have fabricated their spiral resonator, they put it in a dilution refrigerator, pictured above in Bloks lab in Bausch & Lomb Hall. The dilution refrigerator cools the spiral resonator to temperatures close to absolute zero. At these temperatures, the niobium that makes up the spiral resonator becomes superconducting.
SAFE TRAVELS: The team measures and tests the spiral resonators using commercial microwave equipment. During this process, they send electrical signals to the spiral resonator. The signals interact with the resonator and bounce back. From the reflected signal, they can determine the resonators properties. In essence, the researchers are analyzing the electrical components of the circuits, measuring how electricity travels through the metals, and using electrical control signals to control the photons in the metals. Pictured above is graduate student Zihao Wang.
TOO LEGIT QUDIT: The researchers, including graduate students Ray Parker and Liz Champion, then discuss and perfect the process, which could ultimately help in protecting quantum information from noise and assist in quantum error correction. The circuits have a variety of potential applications, including in quantum computing and improving the accuracy of sensors.
Tags: Department of Physics and Astronomy, featured-post, Machiel Blok, quantum science, research funding, School of Arts and Sciences
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Creating superconducting circuits : News Center - University of Rochester
Revolutionary new software can speed up quantum research – Innovation News Network
Quantum research is expected to change many areas of society. However, researchers are certain that many undiscovered quantum properties and applications still need to be explored.
New discoveries could advance areas such as healthcare, communication, defence, and energy.
A paper detailing the research, SuperConga: An open-source framework for mesoscopic superconductivity, was published in Applied Physics Reviews.
In the field of quantum research, scientists are particularly interested in the properties of superconducting quantum particles. These give components perfect conductivity with unique magnetic properties.
These superconducting properties are considered conventional today and have already paved the way for entirely new technologies used in applications such as magnetic resonance imaging equipment, maglev trains, and quantum computer components.
However, years of research and development remain before a quantum computer can be expected to solve real computing problems in practice, for example.
The local density of current-carrying particles in a mesoscopic vortex lattice in a small mesoscopic superconductor
We want to discover all the other exciting properties of unconventional superconductors. Our software is powerful, educational and user-friendly, and we hope that it will help generate new understanding and suggest entirely new applications for these unexplored superconductors, stated Patric Holmvall, Postdoctoral researcher in Condensed Matter Physics at Uppsala University.
Usually, experiments on quantum materials are resource intensive, difficult to interpret, and take years to carry out.
Using their open-source software, titled SuperConga, the team have propelled developments in quantum research. It is free to use and has been specifically designed to perform advanced simulations and analyses of quantum components.
Because the first-of-its-kind software operates at a microscopic level, it can carry out simulations capable of picking up the strange properties of quantum particles and applying them in practice.
Mikael Fogelstrm, Professor of Theoretical Physics at Chalmers, explained: We are specifically interested in unconventional superconductors, which are an enigma in terms of how they even work and their properties.
We know that they have some desirable properties that protect quantum research from interference and fluctuations. Interference is what currently limits us from having a quantum computer that can be used in practice.
He added: This is where basic research into quantum materials is crucial if we are to make any progress.
These tools must be used at the minimal particle level to develop new quantum researcher ideas and scale them up to be used in practice.
This means working at the mesoscopic level, which lies between the interface between the microscopic scale and the macroscopic scale, which measures everyday objects in our world and are subject to the laws of classical physics.
Because of the softwares ability to work at this mesoscopic level, the Chalmers researchers now hope to make life easier for researchers and students working with quantum physics.
Tomas Lfwander, Professor of Applied Quantum Physics at Chalmers, concluded: Extremely simplified models based on either the microscopic or macroscopic scale are often used at present.
This means that they do not manage to identify all the important physics or that they cannot be used in practice.
With this free software, we want to make it easier for others to accelerate and improve their quantum research without having to reinvent the wheel every time.
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Revolutionary new software can speed up quantum research - Innovation News Network