CMP Journal 2025-01-08

Statistics

Physical Review Letters: 7

Physical Review X: 1

Review of Modern Physics: 1

Physical Review Letters

Measurement-Induced Spectral Transition

Research article | Nonequilibrium statistical mechanics | 2025-01-08 05:00 EST

Ken Mochizuki and Ryusuke Hamazaki

We show that noisy quantum dynamics exposed to generalized measurements exhibit a spectral transition between gapless and gapped phases. To this end, we employ the Lyapunov spectrum obtained through singular values of a nonunitary matrix describing the dynamics. We discover that the gapless and gapped phases, respectively, correspond to the volume-law and area-law phases of the entanglement entropy for the dominant Lyapunov vector. This correspondence between the spectral gap and the scaling of entanglement offers an intriguing common structure with ground-state phase transitions. We also discuss some crucial differences from ground-state transitions, such as the extensive entanglement and the exponentially small gaps. Furthermore, we show that the spectral transition leads to the transition of the timescale for the memory loss and purification of initial states.

Phys. Rev. Lett. 134, 010410 (2025)

Nonequilibrium statistical mechanics, Quantum measurements, Quantum phase transitions, Quantum stochastic processes, Weak values & weak measurements, 1-dimensional spin chains, Quantum many-body systems, Qubits, Transfer matrix calculations

Reliability Function of Classical-Quantum Channels

Quantum communication | 2025-01-08 05:00 EST

Ke Li and Dong Yang

Holevo's conjecture is shown to be true: the reliability function of classical-quantum channels has a general lower bound.

Phys. Rev. Lett. 134, 010802 (2025)

Quantum communication, Quantum communication, protocols & technology

High-Temperature QCD Static Potential beyond Leading Order

Research article | Bound states | 2025-01-08 05:00 EST

Margaret E. Carrington, Cristina Manuel, and Joan Soto

We calculate the leading and next-to-leading corrections to the real-time QCD static potential in a high-temperature medium in the region where bound states transit from narrow resonances to wide ones. We find sizable contributions to both the real and the imaginary part of the potential. The calculation involves both loop diagrams calculated in the hard thermal loop effective theory and power corrections to the hard thermal loop Lagrangian calculated in QCD. We compare our results with recent lattice data and check the consistency of different methods used in lattice calculations. We also discuss the usefulness of our results to guide lattice inputs.

Phys. Rev. Lett. 134, 011905 (2025)

Bound states, Effective field theory, Finite temperature field theory, Quantum chromodynamics, Quark-gluon plasma

Operating a Multi-Ion Clock with Dynamical Decoupling

Research article | Atomic, optical & lattice clocks | 2025-01-08 05:00 EST

Nitzan Akerman and Roee Ozeri

We study and characterize a quasicontinuous dynamical decoupling scheme that effectively suppresses dominant frequency shifts in a multi-ion optical clock. Addressing the challenge of inhomogeneous frequency shifts in such systems, our scheme mitigates primary contributors, namely, the electric quadrupole and the linear Zeeman shifts. Based on \(^{88}{\mathrm{Sr}}^{+}\) ions, we implement the scheme in linear chains of up to 7 ions and demonstrate a significant suppression of the shift by more than 3 orders of magnitude, leading to relative frequency inhomogeneity below \(7\times{}{10}^{- 17}\). Additionally, we evaluate the associated systematic shift arising from the radio-frequency drive used in the QCDD scheme, showing that, in the presented realization, its contribution to the systematic relative frequency uncertainty is below \({10}^{- 17}\), with the potential for further improvement. These results provide a promising avenue toward implementing multi-ion clocks exhibiting an order of magnitude or more improvement in stability while maintaining a similar high degree of accuracy to that of single-ion clocks.

Phys. Rev. Lett. 134, 013201 (2025)

Atomic, optical & lattice clocks, Ions, Atom & ion trapping & guiding, Coherent control, Optical spectroscopy

Perturbation Theory for Resonant States near a Bound State in the Continuum

Research article | Metamaterials | 2025-01-08 05:00 EST

Nan Zhang and Ya Yan Lu

In this work, we develop a perturbation theory to analyze resonant states near a bound state in the continuum (BIC) in photonic crystal slabs. The theory allows us to rigorously determine the asymptotic behavior of \(Q\)-factor and the far-field polarization. We show that the resonant states close to a BIC can be nearly circularly polarized if the scattering matrix satisfies a certain condition. Moreover, our theory offers a novel perspective on super-BICs and provides a clear and precise condition to efficiently identify them in both symmetric and asymmetric structures without requiring a merging process. For practical applications, we find a super-BIC in a square lattice of rods on a dielectric substrate. Our theory addresses the non-Hermitian nature of the system, can be generalized to treat other structures that support BICs, and has potential applications in resonance and chiral optics.

Phys. Rev. Lett. 134, 013803 (2025)

Metamaterials, Metasurfaces, Nanophotonics, Photonic crystals, Polarization of light, Perturbative methods

Symmetry Strategy for Rapid Discovery of Abundant Fractional Quantum Ferroelectrics

Research article | Electric polarization | 2025-01-08 05:00 EST

Guoliang Yu, Junyi Ji, Yingwei Chen, Changsong Xu, and H. J. Xiang

Traditional ferroelectrics are limited by Neumann's principle, which confines exploration of ferroelectrics within polar point groups. Our recent work [Ji et al., Nat. Commun. 15, 135 (2024)] proposes the concept of fractional quantum ferroelectricity (FQFE) that extends the playground of ferroelectricity to nonpolar point groups. Here, we apply group theory and introduce an efficient symmetry strategy to identify FQFE candidates. Integrated with a high-throughput screening scheme, we go through 171 527 materials and identify 221 potential FQFE candidates, which are already experimentally synthesized. In addition, we point out for the first time that the essence of FQFE is fractional atomic displacements with respect to lattice vectors, which can actually result in both fractional (type I) and integer (type II) quantized polarization, respectively. Through performing first-principles calculations, we verify the symmetry-predicted switchable FQFE properties in bulk \({\mathrm{AlAgS}}_{2}\) and monolayer \({\mathrm{HgI}}_{2}\). Notably, \({\mathrm{AlAgS}}_{2}\) exhibits an ultralow switching barrier of \(22\text{ }\text{ }\mathrm{meV}/\mathrm{f}.\mathrm{u}.\) and interlocked in-plane/out-of-plane polarization, while \({\mathrm{HgI}}_{2}\) displays large spontaneous polarization of \(42\text{ }\text{ }\mathrm{\mu }\mathrm{C}/{\mathrm{cm}}^{2}\). Our findings not only advance the understanding on FQFE, but also offer guidance for experimental exploration and design of novel ferroelectric materials.

Phys. Rev. Lett. 134, 016801 (2025)

Electric polarization, Ferroelectricity, First-principles calculations, Ferroelectrics, Group theory, High-throughput calculations, Symmetries

Coexistence of Uniform and Oscillatory States Resulting from Nonreciprocity and Conservation Laws

Research article | Bifurcations | 2025-01-08 05:00 EST

Daniel Greve, Giorgio Lovato, Tobias Frohoff-Hülsmann, and Uwe Thiele

Employing a two-species Cahn-Hilliard model with nonreciprocal interactions, we show that the interplay of nonreciprocity and conservation laws results in the robust coexistence of uniform stationary and oscillatory phases as well as of uniform and crystalline phases. For nonequilibrium models with a spurious gradient dynamics structure, such coexistences between two or more nonequilibrium phases and resulting phase diagrams can, nevertheless, be predicted by a Maxwell double-tangent construction. This includes phases with sustained regular or irregular out-of-equilibrium dynamics as further corroborated by bifurcation studies and time simulations.

Phys. Rev. Lett. 134, 018303 (2025)

Bifurcations, Living matter & active matter, Nonequilibrium & irreversible thermodynamics, Pattern formation, Collective dynamics, Dynamical systems

Physical Review X

Scaling Law for Intrinsic Fracture Energy of Diverse Stretchable Networks

Research article | Fatigue | 2025-01-08 05:00 EST

Chase Hartquist, Shu Wang, Qiaodong Cui, Wojciech Matusik, Bolei Deng, and Xuanhe Zhao

The energy required to fracture a lattice material obeys a scaling law governed by just three parameters, researchers find.

Phys. Rev. X 15, 011002 (2025)

Fatigue, Fracture, Metamaterials, Polymers, Materials modeling, Scaling methods

Review of Modern Physics

Using gravitational waves to see the first second of the Universe

Research article | Cosmic strings & domain walls | 2025-01-08 05:00 EST

Rishav Roshan and Graham White

Gravitational waves open a unique window on the earliest times in cosmology because the dense primordial plasma, impenetrable to light or neutrinos, is transparent to gravitational waves up to the instant of the birth of the Universe. This review discusses the possible signals from the phase transitions, topological defects, and other cosmological sources, as well as a range of strategies for detection of the stochastic gravitational waves produced by the earliest events in the history of the Universe.

Rev. Mod. Phys. 97, 015001 (2025)

Cosmic strings & domain walls, Cosmology, Gravitational waves, Inflation, Particle phenomena, Phase transitions