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Light-induced phases, one group of the recently discovered phases, have attracted much interest from scientists in the last ten years since they are thought to offer a viable platform for new solar panels, new chemical platforms, and a new route for contemporary quantum technologies.

A team from the City University of Hong Kong (CityU) led by a physicist recently created a new quantum theory that explains the light-induced phase of matter and forecasts its revolutionary functions. The new theory may completely alter the area of quantum photonics and quantum control at room temperature. It also makes possible several future light-based technologies, including optical communications, quantum computing, and light harvesting.

For light-harvesting devices, energy conversion, and quantum computing, the ultrafast activities of photoactive molecules, such as electron transfer and energy redistribution, typically occurring at the femtosecond scale (1015s), are of utmost relevance.

However, there are many unknowns in the studies on these processes. Since most theories on light-induced phases are constrained by time and energy scales, they cannot explain how short laser pulses affect molecules transient characteristics and ultrafast processes. These place an essential restriction on the study of light-induced phases of matter.

To overcome these challenges, Dr. Zhang and his colleagues created the first-ever unique quantum theory for the optical signals of the light-induced phases of molecules. The new theory circumvents the limitations of earlier theories and methods by using mathematical analysis and numerical simulations to explain the dynamics of molecules in their excited states and their optical properties in real time.

The novel theory combines ultrafast spectroscopy with cutting-edge quantum electrodynamics. It explains the nonlinear dynamics of molecules using contemporary algebra, laying the groundwork for cutting-edge technical applications for lasers and material characterization. Thus, it presents novel optical detection and quantum metrology principles.

Dr. Zhang Zhedong, Assistant Professor of Physics at CityU, who led the study, said,What is particularly fascinating about our new theory is that the cooperative motion of a cluster of molecules shows a wave-like behavior, which spreads over a distance. This was not achievable in conventional studies. And this collective motion can exist at room temperature instead of only in an ultralow, cryogenic temperature previously. This means that precise control and sensing of particle motion may be feasible at room temperature. This may open new research frontiers, such as collective-driven chemistry, that could potentially revolutionize the study of photochemistry.

The development of next-generation light-harvesting and -emitting devices, as well as laser operation and detection, is made easier by the new quantum theory. Bright light emission may result from the coherence from molecular cooperativity caused by light. The researchs spectroscopic probes of the light-induced phase of matter can be used to take advantage of quantum metrology and next-generation optical sensor technologies.

At a larger scale, the light-induced phases may enable various novel light-based interdisciplinary applications, such as optical communications, biological imaging, control of chemical catalysis, and designating light-harvesting devices in an energy-efficient manner.

In the near future, the researchers plan to explore the light-induced phases and their effect on quantum materials and develop new spectroscopic techniques and detection in the context of quantum entanglement.

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A new quantum theory explains the "light-induced phase" of matter - Tech Explorist

NVision Imaging, a developer of MRI polarizers and hyperpolarized imaging agents, announced on Thursday that it has closed a $30 million Series A round, with an additional $19.5 million in funding from the German government. The round was led by Playground Global, with participation by return investors b-to-v and new participation from Pathena Investments, Entre Capital, Lauder Family, ES Kapital, and Ulm Kapital. The Series A brings NVision's total funding to $35 million, not including government funds.

NVision, co-founded by a partially Israeli team of quantum physicists, engineers, and chemists, is headquartered in Ulm, Germany.

While traditional MRIs detect slow-changing effects of a cancer therapy at the tissue level, which can take months to show up from the onset of treatment, metabolic MRIs are able to detect early changes of key metabolic pathways at the cellular level, which can show up within days from starting treatment. Metabolic MRIs rely on polarization, which is where NVision comes in. Based on a novel parahydrogen-induced polarization (PHIP) technique, the NVision team uses quantum physics, chemistry, and engineering in its polarizer.

The impact that this technology will have on medicine is monumental, said Dr. Sella Brosh, CEO of NVision. With more accessibility to this kind of technology and giving doctors more time to choose the right therapy for treatment, we can significantly improve a patients chance of recovery while not subjecting them to toxic treatments that hurt more than they help. Certainty will become the cornerstone of a new, life-altering era of adaptive cancer treatment that gives patients and their loved ones peace of mind.

NVision quantum metabolic polarizers are currently planned for preclinical use in 2023. The company has a partnership with Siemens Healthineers, a leading provider of MRI technology, with plans to deploy systems at over 50 of the worlds top cancer centers by 2025. It has also signed a collaboration with Memorial Sloan Kettering.

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NVision Imaging raises $30 million Series A to bring quantum ... - CTech

Twistronics isn't a new dance move, exercise equipment, or new music fad. No, it's 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," in Nature 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. Chen's 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 Upadhyaya's 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 Chen's group, Dr. Avinash Rustagi (postdoc) from Upadhyaya's 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 Chen's 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 Chen's 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 CrI3 crystals 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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Combining twistronics with spintronics could be the next giant leap ... - Science Daily

Developing commercial fusion energy requires scientists to understand sustained processes that have never before existed on Earth. But with so many unknowns, how do we make sure were designing a device that can successfully harness fusion power?

We can fill gaps in our understanding using computational tools like algorithms and data simulations to knit together experimental data and theory, which allows us to optimize fusion device designs before theyre built, saving much time and resources.

Currently, classical supercomputers are used to run simulations of plasma physics and fusion energy scenarios, but to address the many design and operating challenges that still remain, more powerful computers are a necessity, and of great interest to plasma researchers and physicists.

Quantum computers exponentially faster computing speeds have offered plasma and fusion scientists the tantalizing possibility of vastly accelerated fusion device development. Quantum computers could reconcile a fusion devices many design parameters for example, vessel shape, magnet spacing, and component placement at a greater level of detail, while also completing the tasks faster. However, upgrading to a quantum computer is no simple task.

In a paper, Dyson maps and unitary evolution for Maxwell equations in tensor dielectric media, recently published in Physics Review A, Abhay K. Ram, a research scientist at the MIT Plasma Science and Fusion Center (PSFC), and his co-authors Efstratios Koukoutsis, Kyriakos Hizanidis, and George Vahala present a framework that would facilitate the use of quantum computers to study electromagnetic waves in plasma and its manipulation in magnetic confinement fusion devices.

Quantum computers excel at simulating quantum physics phenomena, but many topics in plasma physics are predicated on the classical physics model. A plasma (which is the dielectric media referenced in the papers title) consists of many particles electrons and ions the collective behaviors of which are effectively described using classic statistical physics. In contrast, quantum effects that influence atomic and subatomic scales are averaged out in classical plasma physics.

Furthermore, the descriptive limitations of quantum mechanics arent suited to plasma. In a fusion device, plasmas are heated and manipulated using electromagnetic waves, which are one of the most important and ubiquitous occurrences in the universe. The behaviors of electromagnetic waves, including how waves are formed and interact with their surroundings, are described by Maxwells equations a foundational component of classical plasma physics, and of general physics as well. The standard form of Maxwells equations is not expressed in quantum terms, however, so implementing the equations on a quantum computer is like fitting a square peg in a round hole: it doesnt work.

Consequently, for plasma physicists to take advantage of quantum computings power for solving problems, classical physics must be translated into the language of quantum mechanics. The researchers tackled this translational challenge, and in their paper, they reveal that a Dyson map can bridge the translational divide between classical physics and quantum mechanics. Maps are mathematical functions that demonstrate how to take an input from one kind of space and transform it to an output that is meaningful in a different kind of space. In the case of Maxwells equations, a Dyson map allows classical electromagnetic waves to be studied in the space utilized by quantum computers. In essence, it reconfigures the square peg so it will fit into the round hole without compromising any physics.

The work also gives a blueprint of a quantum circuit encoded with equations expressed in quantum bits (qubits) rather than classical bits so the equations may be used on quantum computers. Most importantly, these blueprints can be coded and tested on classical computers.

For years we have been studying wave phenomena in plasma physics and fusion energy science using classical techniques. Quantum computing and quantum information science is challenging us to step out of our comfort zone, thereby ensuring that I have not become comfortably numb, says Ram, quoting a Pink Floyd song.

The paper's Dyson map and circuits have put quantum computing power within reach, fast-tracking an improved understanding of plasmas and electromagnetic waves, and putting us that much closer to the ideal fusion device design.

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A new mathematical blueprint is accelerating fusion device ... - MIT News