Symmetry Breaking

Scientists found chiral symmetry breaking in crystals that transforms achiral to chiral structures and creates new optical materials.

Researchers at The University of Osaka have discovered a new type of chiral symmetry breaking (CSB) in an organic crystalline compound.

Life as we know it is based on organic molecules. In these molecules, carbon and hydrogen atoms are linked into a fascinating array of structures, such as chains or rings. One special class of organic molecules, hetero[8]circulenes, can behave in interesting ways because of their ring of eight atoms, and have many applications, including electronic devices responsible for controlling and detecting light.

Almost all animals have symmetrical bodies. Bilateral symmetry is almost universal in all animals and is only very rarely broken—with exceptions like the five-armed starfish or crab species that have one large and one small claw.

Author(s): T. Chouinard and D. M. BrounTo probe spontaneous time reversal symmetry breaking (TRSB) in superconductors at microwave frequencies, the authors propose here a technique based on a doubly degenerate resonator mode, such as the TE 111 mode of a cylindrical cavity. In addition to the frequency splitting induced by TRSB, which can be dwarfed by spurious shape distortions, the authors show that when such a resonator is interrogated by circularly polarized microwaves, the forward and reverse transmission response breaks reciprocity, providing unambiguous evidence that time-reversal symmetry is broken. [Phys. Rev. B 112, 014521] Published Mon Jul 28, 2025

Author(s): Baptiste Debecker, Lukas Pausch, Jonathan Louvet, Thierry Bastin, John Martin, and François DamanetThe authors study how the coupling of a quantum system to a non-Markovian environment can be used to generate and reshape phase transitions and squeezing in matter phases, and introduce the concept of directional spontaneous symmetry breaking. They also propose an experimental implementation of their non-Markovian model in a cavity-QED setup. [Phys. Rev. A 112, 012210] Published Fri Jul 11, 2025

Author(s): Zheng Liu, Mengjie Wei, Wenzhi Peng, Dazhi Hou, Yang Gao, and Qian NiuA new symmetry-breaking scenario provides a comprehensive description of magnetic behavior associated with the anomalous Hall effect. [Phys. Rev. X 15, 031006] Published Mon Jul 07, 2025

For the first time, an international team of scientists has experimentally simulated spontaneous symmetry breaking (SSB) at zero temperature using a superconducting quantum processor. This achievement, which was accomplished with over 80% fidelity, represents a milestone for quantum computing and condensed matter physics.

In a review just published in Nature Materials, researchers take aim at the oldest principle in electronics: Ohm's law.

A research team has observed multibody interaction-induced EPs and hysteresis trajectories in cold Rydberg atomic gases. They revealed the phenomenon of charge-conjugation parity (CP) symmetry breaking in non-Hermitian multibody physics.

Everything in nature has a geometric pattern—from the tiger's stripes and spirals in flowers to the unique fingerprints of each human being. While these patterns are sometimes symmetrical, most of such patterns lack symmetry, which leaves us with one major question: How do such unsymmetrical patterns emerge in nature?

Tiny strains in a crystal can cause electrons to behave in a surprising way that closely resembles a highly sought-after mechanism, RIKEN physicists have found in a new study. Previous studies may need to be re-evaluated in light of this finding.

Author(s): Yoshihito Kuno, Takahiro Orito, and Ikuo IchinoseThere are two kinds of symmetries in quantum mixed states (QMSs) – called strong and weak symmetries– and studying their spontaneous symmetry breaking (SSB) pattern helps classify QMSs, which is an ongoing important issue. The authors study here a decohered cluster model with Z 2 ⊗ Z 2 symmetry and uncover two kinds of symmetry-protected topological (SPT) mixed states. Using doubled Hilbert formalism, they demonstrate a transition between the two states, named strong and double average SPT states, where the latter features coexisting SPT and SSB. [Phys. Rev. B 111, 174110] Published Thu May 15, 2025

Author(s): Yuchen Guo and Shuo YangThe authors uncover here a new quantum phase — the double average symmetry-protected topological (ASPT) phase — that arises uniquely in open quantum systems, where symmetry breaking and topological order coexist. Using the imaginary-time Lindbladian formalism, they establish a rich phase diagram featuring distinct gapless phases and topological triple points. This work highlights how environmental interactions can lead to novel quantum phenomena with no analog in closed systems. [Phys. Rev. B 111, L201108] Published Mon May 12, 2025

The materials that make up all the structures and physical systems around us, including our own bodies, are not perfect—they contain flaws in the form of tiny cracks. When one of these cracks suddenly and rapidly spreads, it can be life-threatening, but the rich, intricate patterns formed by cracks can also be spectacular and intriguing.

Author(s): Qinwen Deng, Hengxin Tan, Brenden R. Ortiz, Stephen D. Wilson, Binghai Yan, and Liang WuThe authors clarify here the microscopic structure and symmetry breaking of the charge density wave phase in the kagome superconductors RbV 3 Sb 5 and KV 3 Sb 5 by ultrafast time-resolved reflectivity. Based on measuring coherent phonon spectra and comparing them to calculated phonon frequencies via density-functional theory, the authors show

Author(s): Zicheng Tao, Tianye Yu, Jianyang Ding, Zhicheng Jiang, Zhenhai Yu, Wei Xia, Xia Wang, Xuerong Liu, Yulin Chen, Dawei Shen, Yan Sun, and Yanfeng GuoThe authors report here that an external magnetic field can selectively break the mirror symmetries along different crystallographic directions in the kagome magnet GdMn 6 Ge 6 , which can thereby realize distinct Berry curvatures and tunable large anomalous Hall conductivities. The results set an explicit example demonstrating that the strong correlation between mirror symmetry and Berry curvature can generate a significant intrinsic anomalous Hall effect, as well as tunable topological

Following Gboard hitting 10 billion Play Store downloads yesterday, the Android keyboard has made a small change to the shortcuts button that lets you access various tools. more…

Author(s): Yoshihito Kuno, Takahiro Orito, and Ikuo IchinoseDecoherence on quantum many-body systems induces nontrivial mixed states with specific properties that have no counterparts in pure states. The authors clarify here the emergence of “intrinsic mixed state topological order” in a toric code state under decoherence, which accompanies exotic anyon proliferation. Furthermore, the authors find that the decoherence-induced phase transition in the stabilizer formalism is described by a percolation picture in two dimensions. The viewpoint of one-form symmetry and its spontaneous symmetry breaking plays an important role in this study. [Phys. Rev. B 111, 064111] Published Wed Feb 19, 2025

Author(s): Bilal Hawashin, Junchen Rong, and Michael M. SchererA local quantum field theory is found to spontaneously break a global symmetry at all temperatures, defying the normal expectation that symmetries get restored at high temperatures. [Phys. Rev. Lett. 134, 041602] Published Tue Jan 28, 2025

Author(s): Amir Hajibabaei, William J. Baldwin, Gábor Csányi, and Stephen J. CoxSimulations of superionic silver iodide show the importance of probing long time scales for this kind of material and reveal a new intermediate phase primarily characterized by a broken cation distribution that gives a mechanism for its observed memory effect. [Phys. Rev. Lett. 134, 026306] Published Fri Jan 17, 2025

Author(s): Haruki Watanabe, Hosho Katsura, and Jong Yeon LeeThere is an infinite family of one-dimensional models exhibiting spontaneous breaking of a U(1) symmetry at zero temperature whose order parameter does not commute with the Hamiltonian. [Phys. Rev. Lett. 133, 176001] Published Thu Oct 24, 2024

The vast majority of organic molecules (based on a carbon structure) are not flat, but have a three-dimensional geometry. Various results can be obtained depending on the way the atoms are arranged inside each molecule. In some cases, a molecule and its mirror image may have completely different properties; we are talking about two symmetric molecules that have the same relationship that an object has with its image in a mirror.

Author(s): Aarti, K. Panda, D. T. Adroja, A. Bhattacharyya, P. K. Biswas, A. D. Hillier, B. Lake, Samar Layek, and V. K. AnandTime-reversal symmetry breaking in the superconducting state is pondered to occur in superconductors having anisotropic or multi-band energy gap, or p - and d -wave pairing superconductivity of unconventional character. Using the muon spin relaxation and rotation technique, here the authors detect the spontaneously generated internal magnetic field that evidence the occurrence of time-reversal symmetry breaking in the superconducting state of a conventional single-band s -wave superconductor

The first materials scientists might have been early humans who — through trial-and-error experiments — discovered the first

The spectral degeneracies emerging as a consequence of parity-time (PT) symmetry exhibit a profound divergence from their conventional counterparts. They possess non-Hermitian nature and are designated as exceptional points (EPs), marking instances where the real and corresponding imaginary portions of specific eigenvalues align perfectly, alongside a coalescence of their associated eigenvectors.

In both the natural world and human society, there commonly exist complex systems, such as climate systems, ecological systems, and network systems. Due to the involvement of numerous interacting elements, complex systems can stay in multiple different states, and their overall behavior generally exhibits randomness and high disorder.

The first materials scientists might have been early humans who—through trial-and-error experiments—discovered the first "cutting-edge" technologies. They found that the best arrowheads and other tools could be made from certain types of natural, structural materials, which at the time included stones and animal bones.

Researchers have induced stable, switchable polarization in monolayer germanium selenide by applying mechanical force, paving the way for novel ultra-thin electronic devices.

Author(s): J. Pišljar, A. Nych, U. Ognysta, A. Petelin, S. Kralj, and I. MuševičUsing thin layers of chiral nematic liquid crystals, researchers have observed the formation dynamics of skyrmions. [Phys. Rev. Lett. 132, 178101] Published Mon Apr 22, 2024

Metal-to-insulator transition—a process that turns materials from a conductor to an insulator—has been a crucial process behind microelectronic switches, nonvolatile memory, and neuromorphic computing materials. In many cases, this transition is accompanied by drastic changes in the electronic or structural symmetry of the material, which can bring about other unintended property changes to the material. It is therefore desired to realize such a transition without breaking the symmetry of the materials.

Author(s): Mário G. Silveirinha, Hugo Terças, and Mauro AntezzaHalf-integer spin systems are characterized by a degenerate ground state. Here, the authors show that the chiral interactions of a spin-½ qubit with the vacuum fluctuations may spontaneously break both the time-reversal and the time-translation symmetries. In the former case, the electron spin becomes anchored along some particular direction of space determined by a geometrical symmetry. In contrast, the latter situation occurs when the intrinsic spin magnetic moment undergoes a cyclic oscillation in the ground state, realizing a time crystal. [Phys. Rev. B 108, 235154] Published Mon Dec 18, 2023

Author(s): N. Azari, M. Yakovlev, N. Rye, S. R. Dunsiger, S. Sundar, M. M. Bordelon, S. M. Thomas, J. D. Thompson, P. F. S. Rosa, and J. E. SonierMuon spin relaxation measurements on a new generation of high-quality flux-grown single crystals show that UTe 2 does not break time-reversal symmetry. [Phys. Rev. Lett. 131, 226504] Published Wed Nov 29, 2023

Author(s): Andrew C. Yuan, Yaar Vituri, Erez Berg, Boris Spivak, and Steven A. KivelsonThe lowest-order Josephson coupling between d -wave superconductors vanishes by symmetry when the twist angle is close to 45 degrees. The authors propose here an “order by disorder” mechanism, whereby spatial fluctuations in the local Josephson coupling generate an effective higher-order coupling, leading to a time reversal symmetry breaking superconducting phase at the twisted interface. This mechanism may offer an explanation for recent experiments in twist junctions between high- T c cuprate superconductors. These findings have broader implications for high-

Exploiting ultra-confined and highly directional polaritons at the nanoscale is essential for developing integrated nanophotonic devices, circuits and chips. High-symmetry crystals have been extensively studied, with a particular focus on hyperbolic polaritons (HPs). However, the in-plane HP propagation in high-symmetry optical crystals usually exhibits four mirror-symmetric beams, which reduces the directionality and energy-transporting efficiency.

Atoms in a crystal form a regular lattice, in which they can move over small distances from their equilibrium positions. Such phonon excitations are represented by quantum states. A superposition of phonon states defines a so-called phonon wavepacket, which is connected with collective coherent oscillations of the atoms in the crystal.

Author(s): M. Schäfer, N. Barnea, and A. GalCharge-symmetry breaking, or CSB, is a fundamental concept in nuclear physics. Adding a Λ hyperon, a sibling of the nucleon with a strange quark, to light nuclei promises new insights as its isospin impurity must impact CSB in mirror hypernuclei, where the only good data available are for A = 4 . The authors use an ansatz that relates the charge-symmetry-breaking Λ N interaction to the

Author(s): Vitaly P. Panov, Jiseon Yang, L. K. Migara, Hyun-Jin Yoon, and Jang-Kun SongA liquid crystal can support traveling waves that demonstrate a new ability to control the molecules’ orientations. [Phys. Rev. Lett. 129, 117801] Published Fri Sep 09, 2022

Author(s): Francesco Fumarola, Bettina Hein, and Kenneth D. MillerScientists may have answered a longstanding question in biophysics: how the brain learns to recognize features in images before a newborn even opens its eyes. [Phys. Rev. X 12, 031024] Published Thu Aug 11, 2022

Author(s): P. Subramanian, E. Knobloch, and P. G. KevrekidisA ring of coupled oscillators can form rogue waves, large-amplitude bursts that are localized in space and time. This paper provides an alternative mechanism for the formation of rogue waves in a dissipative nonlinear lattice system, and describes the effect of varying the coupling strength. [Phys. Rev. E 106, 014212] Published Wed Jul 27, 2022

In an international collaboration, AMOLF researchers have theoretically described and experimentally observed spontaneous symmetry breaking (SSB) in two laser-driven coupled optical cavities. SSB is a universal phenomenon that occurs in many physical systems. It is at the heart of the laser, superconductivity, and the Higgs mechanism, for example. In the case of laser-driven systems like optical cavities, it was not yet understood how SSB occurs. Because laser-driven systems are always in a state imposed by the laser, the nature and manifestation of SSB is completely different from other systems.

Nature keeps a few secrets. While plenty of structures with low symmetry are found in nature, scientists have been confined to high-symmetry designs when synthesizing colloidal crystals, a valuable type of nanomaterial used for chemical and biological sensing and optoelectronic devices.

New strategy uses electron equivalents to create the first rules for synthesizing low-symmetry colloidal crystals, including structures never found in nature.

Over the past few decades, many condensed matter physicists have conducted research focusing on quantum phase transitions that are not clearly associated with a broken symmetry. One reason that these transitions are interesting is that they might underpin the mechanism of high-temperature superconductivity.

Research undertaken by the Universidad Carlos III de Madrid (UC3M) has concluded that sound can be directed to

Research undertaken by the Universidad Carlos III de Madrid (UC3M) has concluded that sound can be directed to a certain place if the sound waves' symmetry is broken. In order to carry out this work, recently published in the journal Nature, researchers used the whispering gallery phenomenon, a circular, vaulted room in which you can hear what is being said in a specific part of the room from anywhere, even if it is being whispered.

Author(s): Hajo Leschke, Chokri Manai, Rainer Ruder, and Simone WarzelA rigorous proof shows for the first time that the replica-symmetry-breaking phase is not immediately destroyed by adding a finite transverse field to a Sherrington-Kirkpatrick model. [Phys. Rev. Lett. 127, 207204] Published Fri Nov 12, 2021

Magic-angle twisted bilayer graphene is a material made of two sheets of graphene placed on top of each other, with one sheet twisted at precisely 1.05 degrees with respect to the other. This material has been found to be a very promising platform for studying different phases of matter, as it combines metallic, superconducting, magnetic and insulating phases in a single crystal.

A better knowledge of the causes of disease, birth defects and genetic syndromes could come from new insights gleaned by RIKEN biologists into how mice embryos develop asymmetry between their left and right sides.

Author(s): Heitor Casasola, Carlos A. Hernaski, Pedro R. S. Gomes, and Paula F. BienzobazFrustrated spin systems exhibit rich physical properties, and this paper presents an exactly solvable example of a frustrated system of quantum spins on a lattice. The authors analyze several quantum phase transitions, characterize the phases, and discuss the mechanism leading to the phase transitions. [Phys. Rev. E 104, 034131] Published Thu Sep 23, 2021

Author(s): Noboru Watanabe and Masahiko TakahashiThe authors report experimental measurements on electron-impact ionization of CO 2 using the angle- and energy-resolved electron-ion-coincidence technique. The results provide experimental evidence of symmetry breaking in electron-impact dissociative ionization of symmetric molecules. [Phys. Rev. A 104, 032812] Published Thu Sep 09, 2021

Author(s): M. S. Martin, S. R. Stroberg, J. D. Holt, and K. G. LeachSuperallowed β decay, resulting when near-exact isospin symmetry exists between the initial and final nuclei, is an important test of the Standard Model. Understanding the minute breaking of isospin in such nuclei is thus crucially important. The authors calculate signatures of isospin breaking in all relevant superallowed systems, starting from underlying two- and three-nucleon forces. While their results agree with experiment, simpler phenomenological models reproduce these effects more accurately, showing that work remains to be done. [Phys. Rev. C 104, 014324] Published Fri Jul 30, 2021

Author(s): Roland Willa, Matthias Hecker, Rafael M. Fernandes, and Jörg SchmalianThis work provides compelling evidence that time-reversal symmetry breaking (TRSB) in the superconducting phase of Sr 2 RuO 4 is due to inhomogeneous strain. Specifically, it demonstrates that strong inhomogeneous strain near crystallographic dislocations can promote a subleading superconducting state and thereby induce local TRSB in an otherwise single-component d -wave superconductor. The winding of the relative phase between the two superconducting condensates near dislocations,

Optoelectronic materials that are capable of converting the energy of light into electricity, and electricity into light, have promising applications as light-emitting, energy-harvesting, and sensing...

Hiromitsu Takeuchi, a lecturer at the Graduate School of Science, Osaka City University, and a researcher at the Nambu Yoichiro Institute of Theoretical and Experimental Physics (NITEP), has theoretically identified the nature of a mysterious topological defect produced by the recently discovered non-equilibrium time evolution of spontaneous symmetry breaking (SSB). Since the SSB realized in this system is like the SSB that has been known to occur in isotropic superconductors and superfluid 4He, it was expected to produce topological defects with vortex-like properties in the fluid, called quantum vortices. However, the topological defect observed in this experiment has a structure that bore little resemblance to the previously mentioned SSB, and its physical properties have been shrouded in mystery. In this research, the idea of applying the Joukowski transform, which is used to calculate the lift of airplane wings, to quantum vortices was introduced for the first time, and the

Author(s): Christopher GutiérrezSensitive photoemission measurements visualize the signatures of a symmetry-broken phase of graphene with carriers of mixed handedness. [Physics 14, 76] Published Wed May 19, 2021

Author(s): Changhua Bao, Hongyun Zhang, Teng Zhang, Xi Wu, Laipeng Luo, Shaohua Zhou, Qian Li, Yanhui Hou, Wei Yao, Liwei Liu, Pu Yu, Jia Li, Wenhui Duan, Hong Yao, Yeliang Wang, and Shuyun ZhouSensitive photoemission measurements visualize the signatures of a symmetry-broken phase of graphene with carriers of mixed handedness. [Phys. Rev. Lett. 126, 206804] Published Wed May 19, 2021

Author(s): Kimberly Hsieh, Vidya Kochat, Tathagata Biswas, Chandra Sekhar Tiwary, Abhishek Mishra, Gopalakrishnan Ramalingam, Aditya Jayaraman, Kamanio Chattopadhyay, Srinivasan Raghavan, Manish Jain, and Arindam GhoshQuantum transport and universal conductance fluctuation measurements show spontaneous breaking of time-reversal symmetry across graphene grain boundaries. [Phys. Rev. Lett. 126, 206803] Published Wed May 19, 2021

Author(s): E. Młyńczak, I. Aguilera, P. Gospodarič, T. Heider, M. Jugovac, G. Zamborlini, C. Tusche, S. Suga, V. Feyer, S. Blügel, L. Plucinski, and C. M. SchneiderQuantum well states are responsible for many fundamental phenomena that oscillate with layer thickness, such as magnetic anisotropy or magnetoresistance. Here, the authors present the magnetization-dependent quantized electronic states of Fe(001), mapped in unprecedented detail using spin-resolved momentum microscopy and high-resolution angle-resolved photoemission. The experimental observations are compared with photoemission simulations, based on the bulk initial electronic band structure, which include quantization of the initial states and broadening of the final states along the wave vector direction perpendicular to the sample surface. [Phys. Rev. B 103, 035134] Published Wed Jan 20,

Author(s): S. Sahar S. Hejazi, Juan Polo, Rashi Sachdeva, and Thomas BuschThe ground state of interacting two-component Bose-Einstein condensates in the presence of an inhomogeneous artificial gauge potential is found to exhibit symmetry breaking in the phase separated regime. This theoretical work explains that this behavior arises as a consequence of the competition between the interaction and the rotational energies.” [Phys. Rev. A 102, 053309] Published Mon Nov 09, 2020

Over the past few years, a growing number of researchers worldwide has been conducting studies investigating the properties and features of so-called twisted van der Waals (vdW) materials. This unique class of materials could be an ideal platform to examine correlated phases that occur as a result of strong interactions between electrons.

Scientists at Tokyo Institute of Technology and Institute of Photonic Sciences have developed a method to generate circularly polarized light from the ultimate symmetrical structure: the sphere. Their approach involves breaking the inherent symmetry of the sphere by electron beam excitation, which allows for precisely controlling the phase and polarization of the emitted light. This method can be used to encode information in the phase and polarization direction of circularly polarized light, enabling novel quantum communication and encryption technologies.

Scientists developed a method to generate circularly polarized light from the ultimate symmetrical structure: the sphere. Their approach involves breaking the inherent symmetry of the sphere by electron beam excitation, which allows for precisely controlling the phase and polarization of the emitted light.

Author(s): J. González and T. StauberDynamical symmetry breaking is a mechanism by which a strong Coulomb interaction can give mass and open a gap in the spectrum of Dirac-like quasiparticles. The authors demonstrate that the large interaction strength in twisted bilayer graphene leads actually to a competition between the breakdown of chiral symmetry and time-reversal symmetry, with a gap being generated by the Dirac and the Haldane masses, respectively. They find quite an abrupt transition between the two phases, indicating the existence of a quantum critical point at the magic angle of twisted bilayer graphene. [Phys. Rev. B 102, 081118(R)] Published Tue Aug 25, 2020

Author(s): T. Shang, S. K. Ghosh, J. Z. Zhao, L.-J. Chang, C. Baines, M. K. Lee, D. J. Gawryluk, M. Shi, M. Medarde, J. Quintanilla, and T. ShirokaThe Zr 3 Ir superconductor exhibits the coexistence of two exotic, and normally distinct, features: mixed singlet-triplet pairing and broken time-reversal symmetry. Mixed singlet-triplet pairing can take place in superconductors whose crystal lattices lack inversion symmetry. This relativistic effect, which does not require the breaking of additional symmetries, nor an unconventional pairing mechanism, is often quite small. Broken time-reversal symmetry, on the other hand, means that the superconducting state is magnetic and necessitates an unconventional pairing mechanism. The coexistence of these two

A column of liquid crystal molecules could form the basis of a new breed of flexible light detectors that have ultrafast responses, an all-RIKEN team has demonstrated.

A response to light usually seen only in inorganic compounds has been realized in organic liquid crystals, opening the way to highly responsive photodetectors.

When a particle is transformed into its antiparticle and its spatial coordinates inverted, the laws of physics are required to stay the same—or so we thought. This symmetry—known as CP symmetry (charge conjugation and parity symmetry) – was considered to be exact until 1964, when a study of the kaon particle system led to the discovery of CP violation.

A joint team, while exploring phase diagrams in dense H2–HD–D2 mixtures, has reported a new discovery in which they found counterintuitive effects of isotopic doping on the phase diagram of H2–HD–D2 molecular alloy.

This odd behavior may promote the material's ability upon cooling to perfectly conduct electricity in a way unexplained by standard theories.

Scientists previously observed this peculiar behavior—characterized by electrons preferentially traveling along one direction, decoupled from the host crystal

Scientists have discovered that the transport of electronic charge in a metallic superconductor containing strontium, ruthenium, and oxygen breaks the rotational symmetry of the underlying crystal lattice. The strontium ruthenate crystal has fourfold rotational symmetry like a square, meaning that it looks identical when turned by 90 degrees (four times to equal a complete 360-degree rotation). However, the electrical resistivity has twofold (180-degree) rotational symmetry like a rectangle.

Author(s): T. Shang, M. Smidman, A. Wang, L.-J. Chang, C. Baines, M. K. Lee, Z. Y. Nie, G. M. Pang, W. Xie, W. B. Jiang, M. Shi, M. Medarde, T. Shiroka, and H. Q. YuanCaPtAs provides a link between correlated magnetic and weakly-correlated noncentrosymmetric superconductors, the latter of which usually exhibit only fully gapped behavior. [Phys. Rev. Lett. 124, 207001] Published Mon May 18, 2020

Over the last decade, artificial intelligence (AI) and its applications such as machine learning have gained pace to revolutionise many industries. As the world gathers more data, the computing power...

Over the last decade, artificial intelligence (AI) and its applications such as machine learning have gained pace to revolutionize many industries. As the world gathers more data, the computing power of hardware systems needs to grow in tandem. Unfortunately, we are facing a future where we will not be able to generate enough energy to power our computational needs.

Coherent light sources are one of the most crucial foundations in both scientific disciplines and advanced applications. As a prominent platform, ultrahigh-Q whispering-gallery mode (WGM) microcavities have witnessed significant developments of novel light sources. However, the intrinsic chiral symmetry of WGM microcavity geometry and the resulting equivalence between the two directions of laser propagation in a cavity severely limits further applications of microlasers.

Author(s): Mohammad Taghinejad, Zihao Xu, Kyu-Tae Lee, Tianquan Lian, and Wenshan CaiUsing a laser, researchers double the frequency of light reflected off a surface, showcasing on-demand, all-optical control of optical effects needed in optoelectronics. [Phys. Rev. Lett. 124, 013901] Published Thu Jan 02, 2020

A recent study from the labs of James Hone (mechanical engineering) and Cory Dean (physics) demonstrates a new way to tune the properties of two-dimensional (2-D) materials simply by adjusting the twist angle between them. The researchers built devices consisting of monolayer graphene encapsulated between two crystals of boron nitride and, by adjusting the relative twist angle between the layers, they were able to create multiple moiré patterns.

Researchers invent a new way to tune the properties of 2D materials by adjusting the twist angle between them; technology enables the development of nanoelectromechanical sensors with applications in astronomy, medicine, search and rescue, and more.

A recent study demonstrates a new way to tune the properties of 2D materials simply by adjusting the twist angle between them. The researchers built devices consisting of monolayer graphene encapsulated between two crystals of boron nitride and, by adjusting the relative twist angle between the layers, they were able to create multiple moiré pattern--''the first time anyone has seen the full rotational dependence of coexisting moiré superlattices in one device.''

Author(s): Dan Sun, Dmitry A. Sokolov, Jack M. Bartlett, Jhuma Sannigrahi, Seunghyun Khim, Pallavi Kushwaha, Dmitry D. Khalyavin, Pascal Manuel, Alexandra S. Gibbs, Hidenori Takagi, Andrew P. Mackenzie, and Clifford W. HicksIn the delafossite lattice structure of the triangular antiferromagnet PdCrO 2 , the interlayer stacking means that the net interlayer exchange interaction is zero. Through neutron scattering measurements under uniaxial stress, the authors show here that magnetism relieves this frustration through a spontaneous tilt of the spins that breaks the threefold rotational symmetry of the nonmagnetic lattice. It is also demonstrated through resistivity measurements that uniaxial stress can suppress thermal magnetic fluctuations within the

Author(s): Ofer Neufeld and Oren CohenA technique based on high harmonic generation is proposed to probe and characterize electric currents in excited atomic and molecular media. [Phys. Rev. Lett. 123, 103202] Published Fri Sep 06, 2019

In a study published in Scientific Reports, a group of researchers affiliated with São Paulo State University (UNESP) in Brazil describes an important theoretical finding that may contribute to the development of quantum computing and spintronics (spin electronics), an emerging technology that uses electron spin or angular momentum rather than electron charge to build faster, more efficient devices.

Many phenomena of the natural world evidence symmetries in their dynamic evolution which help researchers to better understand a system's inner mechanism. In quantum physics, however, these symmetries are not always achieved. In laboratory experiments with ultracold lithium atoms, researchers have shown for the first time the theoretically predicted deviation from classical symmetry.

Many phenomena of the natural world evidence symmetries in their dynamic evolution which help researchers to better understand a system's inner mechanism. In quantum physics, however, these symmetries are not always achieved. In laboratory experiments with ultracold lithium atoms, researchers from the Center for Quantum Dynamics at Heidelberg University have proven for the first time the theoretically predicted deviation from classical symmetry. Their results were published in the journal Science.

In the Standard Model of particle physics, elementary particles acquire their masses by interacting with the Higgs field. This process is governed by a delicate mechanism: electroweak symmetry breaking (EWSB). Although EWSB was first proposed in 1964, it remains among the least understood phenomena of the Standard Model as a large dataset of high-energy particle collisions is required to probe it.

Author(s): Robert L. JackNonequilibrium systems are ubiquitous in nature but many of their properties are still poorly understood. In this work, the author provides an insightful look at this problem by examining large-deviation theory for reversible and irreversible models of growth. [Phys. Rev. E 100, 012140] Published Thu Jul 25, 2019

The bible of particle physics is dying for an upgrade. And physicists may have just the thing: Some particles and forces might look in the mirror and not recognize themselves. That, in itself, would send the so-called Standard Model into a tailspin.

If this fundamental symmetry of the universe doesn’t hold, it could break open new physics.

For the first time, researchers have observed a break in a single quantum system. The observation—and how they made the observation—has potential implications for physics beyond the standard understanding of how quantum particles interact to produce matter and allow the world to function as we know it.

Author(s): Pablo Serna and Adam NahumAn unusual phenomenology is uncovered in a class of (2+1)-dimensional phase transitions. An accurate, yet not exact O(4) symmetry, relating distinct order parameters, emerges at intermediate length scales. At longer scales it becomes apparent that the transition is weakly first order. However, O(4) persists as a symmetry relating the coexisting ground states, implying very unconventional scaling properties. The transition studied is from Naposeel order to a twofold degenerate valence-bond solid. Via dualities, the results have implications for other deconfined critical points with four soft-order parameter components and for two-flavor QED 3 . [Phys. Rev. B 99, 195110] Published Mon May 06, 2019