Estimation of the properties of a physical system with minimal uncertainty is a central task in quantum metrology. Optical phase estimation is at the center of many metrological tasks where the value of a physical parameter is mapped to the phase of an electromagnetic field and single-shot measureme...

[Phys. Rev. Lett. 125, 120505] Published Fri Sep 18, 2020

]]>How a closed interacting quantum many-body system relaxes and dephases as a function of time is a fundamental question in thermodynamic and statistical physics. In this Letter, we analyze and observe the persistent temporal fluctuations after a quantum quench of a tunable long-range interacting tran...

[Phys. Rev. Lett. 125, 120605] Published Fri Sep 18, 2020

]]>We show that the entropy production rate bounds the rate at which physical processes can be performed in stochastic systems far from equilibrium. In particular, we prove the fundamental tradeoff $\u27e8{\dot{S}}_{e}\u27e9\mathcal{T}\ge {k}_{B}$ between the entropy flow $\u27e8{\dot{S}}_{e}\u27e9$ into the reservoirs and the mean time $\mathcal{T}$ to complete any process ...

[Phys. Rev. Lett. 125, 120604] Published Wed Sep 16, 2020

]]>A family of two-qubit gate combinations that can decrease the circuit depth for NISQ processors is demonstrated using gmon superconducting qubits.

[Phys. Rev. Lett. 125, 120504] Published Tue Sep 15, 2020

]]>In this work, we address the question of how a closed quantum system thermalizes in the presence of a random external potential. By investigating the quench dynamics of the isolated quantum spherical $p$-spin model, a paradigmatic model of a mean-field glass, we aim to shed new light on this complex p...

[Phys. Rev. Lett. 125, 120602] Published Tue Sep 15, 2020

]]>A nanomechanical resonator detects and isolates acoustic waves from a remote thermal source.

[Phys. Rev. Lett. 125, 120603] Published Tue Sep 15, 2020

]]>The interaction between the electric dipole moment of a trapped molecular ion and the phonon modes of the confined Coulomb crystal couples the orientation of the molecule to its motion. We consider the practical feasibility of harnessing this interaction to initialize, process, and read out quantum ...

[Phys. Rev. Lett. 125, 120501] Published Mon Sep 14, 2020

]]>Identifying topological properties is a major challenge because, by definition, topological states do not have a local order parameter. While a generic solution to this challenge is not available yet, a broad class of topological states, namely, symmetry-protected topological (SPT) states, can be id...

[Phys. Rev. Lett. 125, 120502] Published Mon Sep 14, 2020

]]>Accurate control of two-level systems is a longstanding problem in quantum mechanics. One such quantum system is the frequency-bin qubit: a single photon existing in superposition of two discrete frequency modes. In this Letter, we demonstrate fully arbitrary control of frequency-bin qubits in a qua...

[Phys. Rev. Lett. 125, 120503] Published Mon Sep 14, 2020

]]>Data structure has a dramatic impact on the properties of neural networks, yet its significance in the established theoretical frameworks is poorly understood. Here we compute the Vapnik-Chervonenkis entropy of a kernel machine operating on data grouped into equally labeled subsets. At variance with...

[Phys. Rev. Lett. 125, 120601] Published Mon Sep 14, 2020

]]>Contrary to conventional wisdom, a sufficiently small, cold object warms to the temperature of its surroundings faster than a warm object cools, according to a new theory.

[Phys. Rev. Lett. 125, 110602] Published Fri Sep 11, 2020

]]>A new method to study the evolution of a nondegenerate quantum system out of equilibrium explains the results of a recent experiment reporting universal quench dynamics of a Bose gas.

[Phys. Rev. Lett. 125, 110404] Published Thu Sep 10, 2020

]]>Quantum networks play a major role in long-distance communication, quantum cryptography, clock synchronization, and distributed quantum computing. Generally, these protocols involve many independent sources sharing entanglement among distant parties that, upon measuring their systems, generate corre...

[Phys. Rev. Lett. 125, 110505] Published Thu Sep 10, 2020

]]>We report the experimental realization of heralded distribution of single-photon path entanglement at telecommunication wavelengths in a repeater-like architecture. The entanglement is established upon detection of a single photon, originating from one of two spontaneous parametric down-conversion p...

[Phys. Rev. Lett. 125, 110506] Published Thu Sep 10, 2020

]]>The entropy production rate associated with broken time-reversal symmetry provides an essential characterization of nanosystems out of equilibrium, from driven colloidal particles to molecular motors. Limited access to the dynamical states is generally expected to hinder the correct estimation of th...

[Phys. Rev. Lett. 125, 110601] Published Thu Sep 10, 2020

]]>We experimentally demonstrate that electrically neutral particles, neutrons, can be used to directly visualize the electrostatic field inside a target volume that can be physically isolated or occupied. Electric field images are obtained using a spin-polarized neutron beam with a recently developed ...

[Phys. Rev. Lett. 125, 110801] Published Thu Sep 10, 2020

]]>We introduce the resource quantifier of weight of resource for convex quantum resource theories of states and measurements with arbitrary resources. We show that it captures the advantage that a resourceful state (measurement) offers over all possible free states (measurements) in the operational ta...

[Phys. Rev. Lett. 125, 110401] Published Wed Sep 09, 2020

]]>A key ingredient in quantum resource theories is a notion of measure. Such as a measure should have a number of fundamental properties, and desirably also a clear operational meaning. Here we show that a natural measure known as the convex weight, which quantifies the resource cost of a quantum devi...

[Phys. Rev. Lett. 125, 110402] Published Wed Sep 09, 2020

]]>Ancilla systems are often indispensable to universal control of a nearly isolated quantum system. However, ancilla systems are typically more vulnerable to environmental noise, which limits the performance of such ancilla-assisted quantum control. To address this challenge of ancilla-induced decoher...

[Phys. Rev. Lett. 125, 110503] Published Wed Sep 09, 2020

]]>A general attenuator ${\mathrm{\Phi}}_{\lambda ,\sigma}$ is a bosonic quantum channel that acts by combining the input with a fixed environment state $\sigma $ in a beam splitter of transmissivity $\lambda $. If $\sigma $ is a thermal state, the resulting channel is a thermal attenuator, whose quantum capacity vanishes for $\lambda \le 1/2$. We study the quantum cap...

[Phys. Rev. Lett. 125, 110504] Published Wed Sep 09, 2020

]]>We consider the problem of local operations and classical communication (LOCC) discrimination between two bipartite pure states of fermionic systems. We show that, contrary to the case of quantum systems, for fermionic systems it is generally not possible to achieve the ideal state discrimination pe...

[Phys. Rev. Lett. 125, 110403] Published Tue Sep 08, 2020

]]>The NV-NMR spectrometer is a promising candidate for detection of NMR signals at the nanoscale. Field inhomogeneities, however, are a major source of noise that limits spectral resolution in state of the art NV-NMR experiments and constitutes a major bottleneck in the development of nanoscale NMR. H...

[Phys. Rev. Lett. 125, 110502] Published Tue Sep 08, 2020

]]>We show that the inherently large interatomic interactions of a Bose-Einstein condensate (BEC) can enhance the sensitivity of a high precision cold-atom gravimeter beyond the shot-noise limit (SNL). Through detailed numerical simulation, we demonstrate that our scheme produces spin-squeezed states w...

[Phys. Rev. Lett. 125, 100402] Published Thu Sep 03, 2020

]]>Motivated by recent progress in the experimental development of quantum simulators based on Rydberg atoms, we introduce and investigate the dynamics of a class of ($1+1$)-dimensional quantum cellular automata. These nonequilibrium many-body models, which are quantum generalizations of the Domany-Kinze...

[Phys. Rev. Lett. 125, 100403] Published Thu Sep 03, 2020

]]>Despite the unquestionable empirical success of quantum theory, witnessed by the recent uprising of quantum technologies, the debate on how to reconcile the theory with the macroscopic classical world is still open. Spontaneous collapse models are one of the few testable solutions so far proposed. I...

[Phys. Rev. Lett. 125, 100404] Published Thu Sep 03, 2020

]]>Entropy produced by erasure of information in finite time can be minimized regardless of the final state by the use of optimal protocols that control the potential landscape.

[Phys. Rev. Lett. 125, 100602] Published Thu Sep 03, 2020

]]>We generalize a standard benchmark of reinforcement learning, the classical cartpole balancing problem, to the quantum regime by stabilizing a particle in an unstable potential through measurement and feedback. We use state-of-the-art deep reinforcement learning to stabilize a quantum cartpole and f...

[Phys. Rev. Lett. 125, 100401] Published Wed Sep 02, 2020

]]>The efficient numerical simulation of nonequilibrium real-time evolution in isolated quantum matter constitutes a key challenge for current computational methods. This holds in particular in the regime of two spatial dimensions, whose experimental exploration is currently pursued with strong efforts...

[Phys. Rev. Lett. 125, 100503] Published Wed Sep 02, 2020

]]>Superresolution techniques based on intensity measurements after a spatial mode decomposition can overcome the precision of diffraction-limited direct imaging. However, realistic measurement devices always introduce finite crosstalk in any such mode decomposition. Here, we show that any nonzero cros...

[Phys. Rev. Lett. 125, 100501] Published Mon Aug 31, 2020

]]>The Rényi entanglement entropy (REE) is an entanglement quantifier considered as a natural generalization of the entanglement entropy. When it comes to stochastic local operations and classical communication (SLOCC), however, only a limited class of the REEs satisfy the monotonicity condition, while...

[Phys. Rev. Lett. 125, 100502] Published Mon Aug 31, 2020

]]>A spin strongly driven by two harmonic incommensurate drives can pump energy from one drive to the other at a quantized average rate, in close analogy with the quantum Hall effect. The pumping rate is a nonzero integer in the topological regime, while the trivial regime does not pump. The dynamical ...

[Phys. Rev. Lett. 125, 100601] Published Mon Aug 31, 2020

]]>High-dimensional entanglement promises to greatly enhance the performance of quantum communication and enable quantum advantages unreachable by qubit entanglement. One of the great challenges, however, is the reliable production, distribution, and local certification of high-dimensional sources of e...

[Phys. Rev. Lett. 125, 090503] Published Fri Aug 28, 2020

]]>The detection of topological phases of matter has become a central issue in recent years. Conventionally, the realization of a specific topological phase in condensed matter physics relies on probing the underlying surface band dispersion or quantum transport signature of a real material, which may ...

[Phys. Rev. Lett. 125, 090502] Published Thu Aug 27, 2020

]]>We present a rigorous explicit expression for an extensive number of local conserved quantities in the $XYZ$ spin-$1/2$ chain with general coupling constants. All the coefficients of operators in each local conserved quantity are calculated. We also confirm that our result can be applied to the case of ...

[Phys. Rev. Lett. 125, 090602] Published Thu Aug 27, 2020

]]>We employ spherical $t$-designs for the systematic construction of solids whose rotational degrees of freedom can be made robust to decoherence due to external fluctuating fields while simultaneously retaining their sensitivity to signals of interest. Specifically, the ratio of signal phase accumulati...

[Phys. Rev. Lett. 125, 090501] Published Wed Aug 26, 2020

]]>Alice and Bob each have half of a pair of entangled qubits. Bob measures his half and then passes his qubit to a second Bob who measures again and so on. The goal is to maximize the number of Bobs that can have an expected violation of the Clauser-Horne-Shimony-Holt (CHSH) Bell inequality with the s...

[Phys. Rev. Lett. 125, 090401] Published Mon Aug 24, 2020

]]>Even in the presence of conservation laws, one can perform arbitrary transformations on a system if given access to a suitable reference frame, since conserved quantities may be exchanged between the system and the frame. Here we explore whether these quantities can be separated into different parts...

[Phys. Rev. Lett. 125, 090601] Published Mon Aug 24, 2020

]]>Quantum hypothesis testing is a central task in the entire field of quantum information theory. Understanding its ultimate limits will give insight into a wide range of quantum protocols and applications, from sensing to communication. Although the limits of hypothesis testing between quantum states...

[Phys. Rev. Lett. 125, 080505] Published Fri Aug 21, 2020

]]>We construct a dynamical decoupling protocol for accurately generating local and global symmetries in general many-body systems. Multiple commuting and noncommuting symmetries can be created by means of a self-similar-in-time (“polyfractal”) drive. The result is an effective Floquet Hamiltonian that...

[Phys. Rev. Lett. 125, 080602] Published Thu Aug 20, 2020

]]>A new method is proposed to accurately infer the temperature of a noninteracting Fermi gas from the nonequilibrium dynamics of impurities.

[Phys. Rev. Lett. 125, 080402] Published Wed Aug 19, 2020

]]>Unsharp measurements are increasingly important for foundational insights in quantum theory and quantum information applications. Here, we report an experimental implementation of unsharp qubit measurements in a sequential communication protocol, based on a quantum random access code. The protocol i...

[Phys. Rev. Lett. 125, 080403] Published Wed Aug 19, 2020

]]>Continuous observation of a mesoscopic mechanical membrane in the quantum regime reveals the entropy production due to quantum measurement.

[Phys. Rev. Lett. 125, 080601] Published Wed Aug 19, 2020

]]>Strong interaction between light and matter waves, such as electron beams in electron microscopes, has recently emerged as a new tool for manipulating the electron wave packets. Here, we systematically investigate electron-light interactions from first principles. We show that enhanced coupling can ...

[Phys. Rev. Lett. 125, 080401] Published Tue Aug 18, 2020

]]>An outstanding challenge for quantum information processing using bosonic systems is Gaussian errors such as excitation loss and added thermal noise errors. Thus, bosonic quantum error correction is essential. Most bosonic quantum error correction schemes encode a finite-dimensional logical qubit or...

[Phys. Rev. Lett. 125, 080503] Published Tue Aug 18, 2020

]]>Researchers halve the number of lasers needed to implement a quantum logic gate between two different atomic species, a feat that could help to create a scalable quantum computer.

[Phys. Rev. Lett. 125, 080504] Published Tue Aug 18, 2020

]]>Weak-value amplification (WVA) is a metrological protocol that amplifies ultrasmall physical effects. However, the amplified outcomes necessarily occur with highly suppressed probabilities, leading to the extensive debate on whether the overall measurement precision is improved in comparison to that...

[Phys. Rev. Lett. 125, 080501] Published Mon Aug 17, 2020

]]>The theory of the asymptotic manipulation of pure bipartite quantum systems can be considered completely understood: the rates at which bipartite entangled states can be asymptotically transformed into each other are fully determined by a single number each, the respective entanglement entropy. In t...

[Phys. Rev. Lett. 125, 080502] Published Mon Aug 17, 2020

]]>Channel multiplexing quantum communication based on exploiting continuous-variable entanglement of optical modes offers great potential to enhance channel capacity and save quantum resource. Here, we present a frequency-comb-type control scheme for simultaneously extracting a lot of entangled sideba...

[Phys. Rev. Lett. 125, 070502] Published Fri Aug 14, 2020

]]>We uncover a local order parameter for measurement-induced phase transitions: the average entropy of a single reference qubit initially entangled with the system. Using this order parameter, we identify scalable probes of measurement-induced criticality that are immediately applicable to advanced qu...

[Phys. Rev. Lett. 125, 070606] Published Fri Aug 14, 2020

]]>The degree of localization of the Harper-Hofstadter model is shown to display striking periodic dependence on phase degrees of freedom, which can depend on the nature of the boundary condition, reminiscent of the Aharonov-Bohm effect. In the context of implementation in a finite ring-shaped lattice ...

[Phys. Rev. Lett. 125, 070401] Published Thu Aug 13, 2020

]]>Eigenstate thermalization is widely accepted as the mechanism behind thermalization in generic isolated quantum systems. Using the example of a single magnetic defect embedded in the integrable spin-$1/2$ $XXZ$ chain, we show that locally perturbing an integrable system can give rise to eigenstate therm...

[Phys. Rev. Lett. 125, 070605] Published Thu Aug 13, 2020

]]>Finite-temperature spin transport in the quantum Heisenberg spin chain is known to be superdiffusive, and has been conjectured to lie in the Kardar-Parisi-Zhang (KPZ) universality class. Using a kinetic theory of transport, we compute the KPZ coupling strength for the Heisenberg chain as a function ...

[Phys. Rev. Lett. 125, 070601] Published Wed Aug 12, 2020

]]>Dicke-like models can describe a variety of physical systems, such as atoms in a cavity or vibrating ion chains. In equilibrium these systems often feature a radical change in their behavior when switching from weak to strong spin-boson interaction. This usually manifests in a transition from a “dar...

[Phys. Rev. Lett. 125, 070604] Published Wed Aug 12, 2020

]]>Generalized hydrodynamics is a recent theory that describes the large scale transport properties of one dimensional integrable models. At the heart of this theory lies an exact quantum-classical correspondence, which states that the flows of the conserved quantities are essentially quasiclassical ev...

[Phys. Rev. Lett. 125, 070602] Published Tue Aug 11, 2020

]]>We propose a thermodynamic refrigeration cycle which uses indefinite causal orders to achieve nonclassical cooling. The cycle cools a cold reservoir while consuming purity in a control qubit. We first show that the application to an input state of two identical thermalizing channels of temperature $T$...

[Phys. Rev. Lett. 125, 070603] Published Tue Aug 11, 2020

]]>Maximally entangled bipartite unitary operators or gates find various applications from quantum information to many-body physics wherein they are building blocks of minimal models of quantum chaos. In the latter case, they are referred to as “dual unitaries.” Dual unitary operators that can create t...

[Phys. Rev. Lett. 125, 070501] Published Mon Aug 10, 2020

]]>We present a general method for approximately contracting tensor networks with an arbitrary connectivity. This enables us to release the computational power of tensor networks to wide use in inference and learning problems defined on general graphs. We show applications of our algorithm in graphical...

[Phys. Rev. Lett. 125, 060503] Published Fri Aug 07, 2020

]]>In open quantum systems, a clear distinction between work and heat is often challenging, and extending the quantum Jarzynski equality to systems evolving under general quantum channels beyond unitality remains an open problem in quantum thermodynamics. In this Letter, we introduce well-defined notio...

[Phys. Rev. Lett. 125, 060602] Published Fri Aug 07, 2020

]]>A new theoretical study identifies fundamental tradeoffs that limit the amount of noise reduction in quantum information systems.

[Phys. Rev. Lett. 125, 060405] Published Thu Aug 06, 2020

]]>Self-testing usually refers to the task of taking a given set of observed correlations that are assumed to arise via a process that is accurately described by quantum theory, and trying to infer the quantum state and measurements. In other words it is concerned with the question of whether we can te...

[Phys. Rev. Lett. 125, 060406] Published Thu Aug 06, 2020

]]>We present an experimental approach to construct a *dephrasure* channel that contains both dephasing and erasure noises and can be used as an efficient tool to study the superadditivity of coherent information. Using a three-fold dephrasure channel, the superadditivity of coherent information is obser...

[Phys. Rev. Lett. 125, 060502] Published Thu Aug 06, 2020

]]>Quantum coherence is a fundamental resource that quantum technologies exploit to achieve performance beyond that of classical devices. A necessary prerequisite to achieve this advantage is the ability of measurement devices to detect coherence from the measurement statistics. Based on a recently dev...

[Phys. Rev. Lett. 125, 060404] Published Wed Aug 05, 2020

]]>Strongly correlated Fermi systems with pairing interactions become superfluid below a critical temperature ${T}_{c}$. The extent to which such pairing correlations alter the behavior of the liquid at temperatures $T>{T}_{c}$ is a subtle issue that remains an area of debate, in particular regarding the appearan...

[Phys. Rev. Lett. 125, 060403] Published Tue Aug 04, 2020

]]>We propose an all-linear-optical scheme to ballistically generate a cluster state for measurement-based topological fault-tolerant quantum computation using hybrid photonic qubits entangled in a continuous-discrete domain. Availability of near-deterministic Bell-state measurements on hybrid qubits i...

[Phys. Rev. Lett. 125, 060501] Published Tue Aug 04, 2020

]]>We investigate an unconventional symmetry in time-periodically driven systems, the Floquet dynamical symmetry (FDS). Unlike the usual symmetries, the FDS gives symmetry sectors that are equidistant in the Floquet spectrum and protects quantum coherence between them from dissipation and dephasing, le...

[Phys. Rev. Lett. 125, 060601] Published Tue Aug 04, 2020

]]>The emergence of a compressible insulator phase, known as the Bose glass, is characteristic of the interplay of interactions and disorder in correlated Bose fluids. While widely studied in tight-binding models, its observation remains elusive owing to stringent temperature effects. Here we show that...

[Phys. Rev. Lett. 125, 060401] Published Mon Aug 03, 2020

]]>Using an ensemble of atoms in an optical cavity, we engineer a family of nonlocal Heisenberg Hamiltonians with continuously tunable anisotropy of the spin-spin couplings. We thus gain access to a rich phase diagram, including a paramagnetic-to-ferromagnetic Ising phase transition that manifests as a...

[Phys. Rev. Lett. 125, 060402] Published Mon Aug 03, 2020

]]>The fluctuation-dissipation theorem (FDT) is a hallmark of thermal equilibrium systems in the Gibbs state. We address the question whether the FDT is obeyed by isolated quantum systems in an energy eigenstate. In the framework of the eigenstate thermalization hypothesis, we derive the formal express...

[Phys. Rev. Lett. 125, 050603] Published Fri Jul 31, 2020

]]>The study of stronger-than-quantum effects is a fruitful line of research that provides valuable insight into quantum theory. Unfortunately, traditional bipartite steering scenarios can always be explained by quantum theory. Here, we show that, by relaxing this traditional setup, bipartite steering ...

[Phys. Rev. Lett. 125, 050404] Published Wed Jul 29, 2020

]]>We demonstrate the existence of finite-component multicriticality in a qubit-boson model where biased qubits collectively coupled to a single-mode bosonic field. The interplay between biases and boson-qubit coupling produces a rich phase diagram which shows multiple superradiant phases and phase bou...

[Phys. Rev. Lett. 125, 050402] Published Tue Jul 28, 2020

]]>Fourth- and fifth-order virial expansion coefficients of a spin-1/2 Fermi gas are theoretically determined from weak coupling to the unitary point.

[Phys. Rev. Lett. 125, 050403] Published Tue Jul 28, 2020

]]>We study quantum fluctuations of macroscopic parameters of a nonlinear Schrödinger breather—a nonlinear superposition of two solitons, which can be created by the application of a fourfold quench of the scattering length to the fundamental soliton in a self-attractive quasi-one-dimensional Bose gas....

[Phys. Rev. Lett. 125, 050405] Published Tue Jul 28, 2020

]]>A fundamental question in the theory of quantum computation is to understand the ultimate space-time resource costs for performing a universal set of logical quantum gates to arbitrary precision. Here we demonstrate that non-Abelian anyons in Turaev-Viro quantum error correcting codes can be moved o...

[Phys. Rev. Lett. 125, 050502] Published Tue Jul 28, 2020

]]>A new statistical model that optimizes a system’s output could help to maximize the efficiency of mechanical systems.

[Phys. Rev. Lett. 125, 050602] Published Tue Jul 28, 2020

]]>The phase of de Broglie matter waves is a sensitive probe for small forces. In particular, the attractive van der Waals force experienced by polarizable atoms in the close vicinity of neutral surfaces is of importance in nanoscale systems. It results in a phase shift that can be observed in matter-w...

[Phys. Rev. Lett. 125, 050401] Published Mon Jul 27, 2020

]]>An open question in quantum optics is how to manipulate and control complex quantum states in an experimentally feasible way. Here we present concepts for transformations of high-dimensional multiphotonic quantum systems. The proposals rely on two new ideas: (i) a novel high-dimensional quantum nond...

[Phys. Rev. Lett. 125, 050501] Published Mon Jul 27, 2020

]]>We use quantum estimation theory to derive a thermodynamic uncertainty relation in Markovian open quantum systems, which bounds the fluctuation of continuous measurements. The derived quantum thermodynamic uncertainty relation holds for arbitrary continuous measurements satisfying a scaling conditio...

[Phys. Rev. Lett. 125, 050601] Published Mon Jul 27, 2020

]]>We introduce a framework to decompose a bosonic mode into two virtual subsystems—a logical qubit and a gauge mode. This framework allows the entire toolkit of qubit-based quantum information to be applied in the continuous-variable setting. We give a detailed example based on a modular decomposition...

[Phys. Rev. Lett. 125, 040501] Published Fri Jul 24, 2020

]]>Quantum entanglement is a key physical resource in quantum information processing that allows for performing basic quantum tasks such as teleportation and quantum key distribution, which are impossible in the classical world. Ever since the rise of quantum information theory, it has been an open pro...

[Phys. Rev. Lett. 125, 040502] Published Fri Jul 24, 2020

]]>The evolution with a complex Hamiltonian generally leads to information scrambling. A time-reversed dynamics unwinds this scrambling and thus leads to the original information recovery. We show that if the scrambled information is, in addition, partially damaged by a local measurement, then such a d...

[Phys. Rev. Lett. 125, 040605] Published Fri Jul 24, 2020

]]>In the Aharonov-Bohm (AB) effect, a superposed charge acquires a detectable phase by enclosing an infinite solenoid, in a region where the solenoid’s electric and magnetic fields are zero. Its generation seems therefore explainable only by the local action of gauge-dependent potentials, not of gauge...

[Phys. Rev. Lett. 125, 040401] Published Wed Jul 22, 2020

]]>We study the connection between the charging power of quantum batteries and the fluctuations of the extractable work. We prove that in order to have a nonzero rate of change of the extractable work, the state ${\rho}_{\mathcal{W}}$ of the battery cannot be an eigenstate of a “free energy operator,” defined by $\mathcal{F}\equiv {H}_{\mathcal{W}}+{\beta}^{-1}\mathrm{l...}$

[Phys. Rev. Lett. 125, 040601] Published Wed Jul 22, 2020

]]>Scintillators are central for detection of $\gamma $-ray, x-ray, and high energy particles in various applications, all seeking higher scintillation yield and rate. However, these are limited by the intrinsic isotropy of spontaneous emission of the scintillation light and its inefficient outcoupling. We pro...

[Phys. Rev. Lett. 125, 040801] Published Wed Jul 22, 2020

]]>Long-range interacting spin systems are ubiquitous in physics and exhibit a variety of ground-state disorder-to-order phase transitions. We consider a prototype of infinite-range interacting models known as the Lipkin-Meshkov-Glick model describing the collective interaction of $N$ spins and investiga...

[Phys. Rev. Lett. 125, 040602] Published Tue Jul 21, 2020

]]>We introduce the asymmetric extension of the quantum symmetric simple exclusion process which is a stochastic model of fermions on a lattice hopping with random amplitudes. In this setting, we analytically show that the time-integrated current of fermions defines a height field that exhibits quantum...

[Phys. Rev. Lett. 125, 040603] Published Tue Jul 21, 2020

]]>Energy transport in one-dimensional chains of particles with three conservation laws is generically anomalous and belongs to the Kardar-Parisi-Zhang dynamical universality class. Surprisingly, some examples where an apparent normal heat diffusion is found over a large range of length scales were rep...

[Phys. Rev. Lett. 125, 040604] Published Tue Jul 21, 2020

]]>The initialization of a quantum system into a certain state is a crucial aspect of quantum information science. While a variety of measurement strategies have been developed to characterize how well the system is initialized, for a given one, there is in general a trade-off between its efficiency an...

[Phys. Rev. Lett. 125, 030506] Published Fri Jul 17, 2020

]]>The interaction between free electrons and optical near fields is attracting increasing attention as a way to manipulate the electron wave function in space, time, and energy. Relying on currently attainable experimental capabilities, we design optical near-field plates to imprint a lateral phase on...

[Phys. Rev. Lett. 125, 030801] Published Fri Jul 17, 2020

]]>Experiments generate self-reinforcing magnetic waves in a condensate containing both spin-up and spin-down atoms.

[Phys. Rev. Lett. 125, 030401] Published Wed Jul 15, 2020

]]>Experiments generate self-reinforcing magnetic waves in a condensate containing both spin-up and spin-down atoms.

[Phys. Rev. Lett. 125, 030402] Published Wed Jul 15, 2020

]]>We introduce a new family of quantum circuits for which the scrambling of a subspace of nonlocal operators is classically simulable. We call these circuits “super-Clifford circuits” since the Heisenberg time evolution of these operators corresponds to Clifford evolution in operator space. Thus we ar...

[Phys. Rev. Lett. 125, 030502] Published Wed Jul 15, 2020

]]>Currently, there are intense experimental efforts to realize lattice gauge theories in quantum simulators. Except for specific models, however, practical quantum simulators can never be fine-tuned to perfect local gauge invariance. There is thus a strong need for a rigorous understanding of gauge-in...

[Phys. Rev. Lett. 125, 030503] Published Wed Jul 15, 2020

]]>We analyze the dynamics of entanglement entropy in a generic quantum many-body open system from the perspective of quantum information and error corrections. We introduce a random unitary circuit model with intermittent projective measurements, in which the degree of information scrambling by the un...

[Phys. Rev. Lett. 125, 030505] Published Wed Jul 15, 2020

]]>A tremendous amount of recent attention has focused on characterizing the dynamical properties of periodically driven many-body systems. Here, we use a novel numerical tool termed “density matrix truncation” (DMT) to investigate the late-time dynamics of large-scale Floquet systems. We find that DMT...

[Phys. Rev. Lett. 125, 030601] Published Wed Jul 15, 2020

]]>Quantum computers have the potential to speed up certain problems that are hard for classical computers. Hybrid systems, such as the nitrogen-vacancy (NV) center in diamond, are among the most promising systems to implement quantum computing, provided the control of the different types of qubits can...

[Phys. Rev. Lett. 125, 030501] Published Tue Jul 14, 2020

]]>Rotational misalignment or twisting of two monolayers of graphene strongly influences its electronic properties. Structurally, twisting leads to large periodic supercell structures, which in turn can support intriguing strongly correlated behavior. Here, we propose a highly tunable scheme to synthet...

[Phys. Rev. Lett. 125, 030504] Published Tue Jul 14, 2020

]]>We analyze and experimentally demonstrate quantum steering using criteria based on generalized entropies and criteria with minimal assumptions based on the so-called dimension-bounded steering. Further, we investigate and compare their robustness against experimental imperfections such as misalignme...

[Phys. Rev. Lett. 125, 020404] Published Fri Jul 10, 2020

]]>A new measurement protocol is defined for a Mach-Zehnder geometry with a finite signal when quantum interference is concerned, but vanishes for classical waves or particles.

[Phys. Rev. Lett. 125, 020405] Published Fri Jul 10, 2020

]]>Quantum simulation, as a state-of-the-art technique, provides a powerful way to explore topological quantum phases beyond natural limits. Nevertheless, it is usually hard to simulate both the bulk and surface topological physics at the same time to reveal their correspondence. Here we build up a qua...

[Phys. Rev. Lett. 125, 020504] Published Fri Jul 10, 2020

]]>We experimentally realize a method to produce nonequilibrium Bose-Einstein condensates with condensed fraction exceeding those of equilibrium samples with the same parameters. To do this, we immerse an ultracold Bose gas of ${}^{87}\mathrm{Rb}$ in a cloud of ${}^{39}\mathrm{K}$ with substantially higher temperatures, providing a c...

[Phys. Rev. Lett. 125, 020403] Published Wed Jul 08, 2020

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