Pub Date : 2024-04-29DOI: 10.1103/physrevx.14.021020
M. Ferraro, F. Mangini, F. O. Wu, M. Zitelli, D. N. Christodoulides, S. Wabnitz
Recent studies have shown that light propagating in a nonlinear, highly multimode system can thermalize in a manner totally analogous to that encountered in traditional statistical mechanics. At thermal equilibrium, the system’s entropy is at a maximum, in full accord with the second law of thermodynamics. In such arrangements, the entropy is extremized once the statistical power allocation among modes associated with this photon gas attains a Rayleigh-Jeans distribution that is fully characterized by an optical temperature and a chemical potential . However, it has been theoretically argued that the variables and represent actual thermodynamic forces that control the exchange of the respective conjugate quantities between two subsystems. In this work, we report, for the first time, optical calorimetric measurements in nonlinear multimode fibers, which unambiguously demonstrate that both the temperature and the chemical potential dictate the flow of their associated extensive quantities, i.e., the energy and the optical power. Specifically, we study the process of light thermalization associated with two orthogonally polarized laser beams. Our observations are enabled by recently developed techniques that allow one to judiciously multiplex/demultiplex the optical power within various mode groups. Our results indicate that because of photon-photon collisions, “heat” only flows from a hot to a cold photon gas subsystem—thus providing an unequivocal demonstration of the second law in such all-optical thermodynamic arrangements. In addition to being fundamental, our findings provide a new approach to manipulate laser beams using thermodynamic principles.
最近的研究表明，在非线性、高度多模系统中传播的光可以以完全类似于传统统计力学中遇到的方式热化。在热平衡状态下，系统的熵处于最大值，完全符合热力学第二定律。在这种情况下，一旦与这种光子气体相关的模式之间的统计功率分配达到雷利-让斯分布，熵就会达到极值，该分布完全由光学温度 T 和化学势 μ 来表征。然而，理论上有人认为，变量 T 和 μ 代表控制两个子系统之间各自共轭量交换的实际热动力。在这项工作中，我们首次报告了在非线性多模光纤中进行的光学量热测量，明确地证明了温度 T 和化学势 μ 都决定了其相关广泛量（即能量和光功率）的流动。具体来说，我们研究了与两束正交偏振激光束相关的光热化过程。我们的观测工作得益于最新开发的技术，这些技术允许我们在各种模式组内对光功率进行明智的多路复用/解复用。我们的研究结果表明，由于光子-光子碰撞，"热量 "只会从热光子气体子系统流向冷光子气体子系统--因此在这种全光热力学安排中，第二定律得到了明确的证明。除了基本原理之外，我们的发现还提供了一种利用热力学原理操纵激光束的新方法。
{"title":"Calorimetry of Photon Gases in Nonlinear Multimode Optical Fibers","authors":"M. Ferraro, F. Mangini, F. O. Wu, M. Zitelli, D. N. Christodoulides, S. Wabnitz","doi":"10.1103/physrevx.14.021020","DOIUrl":"https://doi.org/10.1103/physrevx.14.021020","url":null,"abstract":"Recent studies have shown that light propagating in a nonlinear, highly multimode system can thermalize in a manner totally analogous to that encountered in traditional statistical mechanics. At thermal equilibrium, the system’s entropy is at a maximum, in full accord with the second law of thermodynamics. In such arrangements, the entropy is extremized once the statistical power allocation among modes associated with this photon gas attains a Rayleigh-Jeans distribution that is fully characterized by an optical temperature <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>T</mi></math> and a chemical potential <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>μ</mi></math>. However, it has been theoretically argued that the variables <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>T</mi></math> and <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>μ</mi></math> represent actual thermodynamic forces that control the exchange of the respective conjugate quantities between two subsystems. In this work, we report, for the first time, optical calorimetric measurements in nonlinear multimode fibers, which unambiguously demonstrate that both the temperature <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>T</mi></math> and the chemical potential <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>μ</mi></math> dictate the flow of their associated extensive quantities, i.e., the energy and the optical power. Specifically, we study the process of light thermalization associated with two orthogonally polarized laser beams. Our observations are enabled by recently developed techniques that allow one to judiciously multiplex/demultiplex the optical power within various mode groups. Our results indicate that because of photon-photon collisions, “heat” only flows from a hot to a cold photon gas subsystem—thus providing an unequivocal demonstration of the second law in such all-optical thermodynamic arrangements. In addition to being fundamental, our findings provide a new approach to manipulate laser beams using thermodynamic principles.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":null,"pages":null},"PeriodicalIF":12.5,"publicationDate":"2024-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140808342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-29DOI: 10.1103/physrevx.14.021021
Ljiljana Stojanović, Jack Coker, Samuele Giannini, Giacomo Londi, Anders S. Gertsen, Jens Wenzel Andreasen, Jun Yan, Gabriele D’Avino, David Beljonne, Jenny Nelson, Jochen Blumberger
Nonfullerene acceptors have caused a step change in organic optoelectronics research but little is known about the mechanism and factors limiting charge transport in these molecular materials. Here a joint computational-experimental investigation is presented to understand the impact of various sources of disorder on the electron transport in the nonfullerene acceptor O-IDTBR. We find that in single crystals of this material, electron transport occurs in the transient quantum delocalization regime with the excess charge delocalized over about three molecules on average, according to quantum-classical nonadiabatic molecular-dynamics simulations. In this regime, carrier delocalization and charge mobility () are limited by dynamical disorder of off-diagonal and diagonal electron-phonon coupling. In molecular assemblies representing disordered thin films, the additional static disorder of off-diagonal electron-phonon coupling is sufficient to fully localize the excess electron on single molecules, concomitant with a transition of transport mechanism from transient quantum delocalization to small polaron hopping and a drop in electron mobility by about 1 order of magnitude. Yet, inclusion of static diagonal disorder resulting from electrostatic interactions arising from the acceptor-donor-acceptor (A-D-A) structure of O-IDTBR, are found to have the most dramatic impact on carrier mobility, resulting in a further drop of electron mobility by about 4–5 orders of magnitude to , in good agreement with thin-film electron mobility estimated from space-charge-limited-current measurements. Limitations due to diagonal disorder caused by electrostatic interactions are likely to apply to most nonfullerene acceptors. They imply that while A-D-A or A-DAD-A motifs are beneficial for photoabsorption and exciton transport, the electrostatic disorder they create can limit carrier transport in thin-film optoelectronic applications. This work shows the value of computational methods, in particular, nonadiabatic molecular-dynamics propagation of charge carriers, to distinguish different regimes of transport for different ty
{"title":"Disorder-Induced Transition from Transient Quantum Delocalization to Charge Carrier Hopping Conduction in a Nonfullerene Acceptor Material","authors":"Ljiljana Stojanović, Jack Coker, Samuele Giannini, Giacomo Londi, Anders S. Gertsen, Jens Wenzel Andreasen, Jun Yan, Gabriele D’Avino, David Beljonne, Jenny Nelson, Jochen Blumberger","doi":"10.1103/physrevx.14.021021","DOIUrl":"https://doi.org/10.1103/physrevx.14.021021","url":null,"abstract":"Nonfullerene acceptors have caused a step change in organic optoelectronics research but little is known about the mechanism and factors limiting charge transport in these molecular materials. Here a joint computational-experimental investigation is presented to understand the impact of various sources of disorder on the electron transport in the nonfullerene acceptor O-IDTBR. We find that in single crystals of this material, electron transport occurs in the transient quantum delocalization regime with the excess charge delocalized over about three molecules on average, according to quantum-classical nonadiabatic molecular-dynamics simulations. In this regime, carrier delocalization and charge mobility (<math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mrow><mi>μ</mi></mrow><mrow><mi>a</mi></mrow></msub><mo>=</mo><mn>7</mn><mtext> </mtext><mtext> </mtext><msup><mrow><mi>cm</mi></mrow><mrow><mn>2</mn></mrow></msup><mtext> </mtext><msup><mrow><mi mathvariant=\"normal\">V</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup><mtext> </mtext><msup><mrow><mi mathvariant=\"normal\">s</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math>) are limited by dynamical disorder of off-diagonal and diagonal electron-phonon coupling. In molecular assemblies representing disordered thin films, the additional static disorder of off-diagonal electron-phonon coupling is sufficient to fully localize the excess electron on single molecules, concomitant with a transition of transport mechanism from transient quantum delocalization to small polaron hopping and a drop in electron mobility by about 1 order of magnitude. Yet, inclusion of static diagonal disorder resulting from electrostatic interactions arising from the acceptor-donor-acceptor (A-D-A) structure of O-IDTBR, are found to have the most dramatic impact on carrier mobility, resulting in a further drop of electron mobility by about 4–5 orders of magnitude to <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mn>10</mn><mrow><mo>−</mo><mn>5</mn></mrow></msup><mtext> </mtext><mtext> </mtext><msup><mrow><mi>cm</mi></mrow><mn>2</mn></msup><mtext> </mtext><msup><mi mathvariant=\"normal\">V</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup><mtext> </mtext><msup><mi mathvariant=\"normal\">s</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math>, in good agreement with thin-film electron mobility estimated from space-charge-limited-current measurements. Limitations due to diagonal disorder caused by electrostatic interactions are likely to apply to most nonfullerene acceptors. They imply that while A-D-A or A-DAD-A motifs are beneficial for photoabsorption and exciton transport, the electrostatic disorder they create can limit carrier transport in thin-film optoelectronic applications. This work shows the value of computational methods, in particular, nonadiabatic molecular-dynamics propagation of charge carriers, to distinguish different regimes of transport for different ty","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":null,"pages":null},"PeriodicalIF":12.5,"publicationDate":"2024-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140814572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-26DOI: 10.1103/physrevx.14.021019
A. Marquet, A. Essig, J. Cohen, N. Cottet, A. Murani, E. Albertinale, S. Dupouy, A. Bienfait, T. Peronnin, S. Jezouin, R. Lescanne, B. Huard
Cat qubits, for which logical and are coherent states of a harmonic mode, offer a promising route towards quantum error correction. Using dissipation to our advantage so that photon pairs of the harmonic mode are exchanged with single photons of its environment, it is possible to stabilize the logical states and exponentially increase the bit-flip time of the cat qubit with the photon number . A large two-photon dissipation rate ensures fast qubit manipulation and short error-correction cycles, which are instrumental to correct the remaining phase-flip errors in a repetition code of cat qubits. Here, we introduce and operate an autoparametric superconducting circuit that couples a mode containing the cat qubit to a lossy mode whose frequency is set at twice that of the cat mode. This passive coupling does not require a parametric pump, and it reaches a rate . With such a strong two-photon dissipation, bit-flip errors of the autoparametric cat qubit are prevented for a characteristic time up to 0.3 s with only a mild impact on phase-flip errors. In addition, we illustrate how the phase of a quantum superposition between and can be arbitrarily changed by driving the harmonic mode while keeping the engineered dissipation active.
{"title":"Autoparametric Resonance Extending the Bit-Flip Time of a Cat Qubit up to 0.3 s","authors":"A. Marquet, A. Essig, J. Cohen, N. Cottet, A. Murani, E. Albertinale, S. Dupouy, A. Bienfait, T. Peronnin, S. Jezouin, R. Lescanne, B. Huard","doi":"10.1103/physrevx.14.021019","DOIUrl":"https://doi.org/10.1103/physrevx.14.021019","url":null,"abstract":"Cat qubits, for which logical <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mo stretchy=\"false\">|</mo><mn>0</mn><mo stretchy=\"false\">⟩</mo></math> and <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mo stretchy=\"false\">|</mo><mn>1</mn><mo stretchy=\"false\">⟩</mo></math> are coherent states <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mo stretchy=\"false\">|</mo><mo>±</mo><mi>α</mi><mo stretchy=\"false\">⟩</mo></math> of a harmonic mode, offer a promising route towards quantum error correction. Using dissipation to our advantage so that photon pairs of the harmonic mode are exchanged with single photons of its environment, it is possible to stabilize the logical states and exponentially increase the bit-flip time of the cat qubit with the photon number <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mo stretchy=\"false\">|</mo><mi>α</mi><msup><mo stretchy=\"false\">|</mo><mn>2</mn></msup></math>. A large two-photon dissipation rate <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>κ</mi><mn>2</mn></msub></math> ensures fast qubit manipulation and short error-correction cycles, which are instrumental to correct the remaining phase-flip errors in a repetition code of cat qubits. Here, we introduce and operate an autoparametric superconducting circuit that couples a mode containing the cat qubit to a lossy mode whose frequency is set at twice that of the cat mode. This passive coupling does not require a parametric pump, and it reaches a rate <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>κ</mi><mn>2</mn></msub><mo>/</mo><mn>2</mn><mi>π</mi><mo>≈</mo><mn>2</mn><mtext> </mtext><mtext> </mtext><mi>MHz</mi></math>. With such a strong two-photon dissipation, bit-flip errors of the autoparametric cat qubit are prevented for a characteristic time up to 0.3 s with only a mild impact on phase-flip errors. In addition, we illustrate how the phase of a quantum superposition between <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mo stretchy=\"false\">|</mo><mi>α</mi><mo stretchy=\"false\">⟩</mo></math> and <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mo stretchy=\"false\">|</mo><mo>−</mo><mi>α</mi><mo stretchy=\"false\">⟩</mo></math> can be arbitrarily changed by driving the harmonic mode while keeping the engineered dissipation active.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":null,"pages":null},"PeriodicalIF":12.5,"publicationDate":"2024-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140648906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-25DOI: 10.1103/physrevx.14.021018
Sheng Zhang, Jixuan Shi, Zhaibin Cui, Ye Wang, Yukai Wu, Luming Duan, Yunfei Pu
Quantum networks can enable various applications such as distributed quantum computing, long-distance quantum communication, and network-based quantum sensing with unprecedented performances. One of the most important building blocks for a quantum network is a photonic quantum memory which serves as the interface between the communication channel and the local functional unit. A programmable quantum memory which can process a large stream of flying qubits and fulfill the requirements of multiple core functions in a quantum network is still to be realized. Here we report a high-performance quantum memory which can simultaneously store 72 optical qubits carried by 144 spatially separated atomic ensembles and support up to a thousand consecutive write or read operations in a random access way, 2 orders of magnitude larger than the previous record. Because of the built-in programmability, this quantum memory can be adapted on demand for several functions. As example applications, we realize quantum queue, stack, and buffer which closely resemble the counterpart devices for classical information processing. We further demonstrate the storage and reshuffle of four entangled pairs of photonic pulses with probabilistic arrival time and arbitrary release order via the memory, which is an essential requirement for the realization of quantum repeaters and efficient routing in quantum networks. Realization of this multipurpose programmable quantum memory thus constitutes a key enabling building block for future large-scale fully functional quantum networks.
{"title":"Realization of a Programmable Multipurpose Photonic Quantum Memory with Over-Thousand Qubit Manipulations","authors":"Sheng Zhang, Jixuan Shi, Zhaibin Cui, Ye Wang, Yukai Wu, Luming Duan, Yunfei Pu","doi":"10.1103/physrevx.14.021018","DOIUrl":"https://doi.org/10.1103/physrevx.14.021018","url":null,"abstract":"Quantum networks can enable various applications such as distributed quantum computing, long-distance quantum communication, and network-based quantum sensing with unprecedented performances. One of the most important building blocks for a quantum network is a photonic quantum memory which serves as the interface between the communication channel and the local functional unit. A programmable quantum memory which can process a large stream of flying qubits and fulfill the requirements of multiple core functions in a quantum network is still to be realized. Here we report a high-performance quantum memory which can simultaneously store 72 optical qubits carried by 144 spatially separated atomic ensembles and support up to a thousand consecutive write or read operations in a random access way, 2 orders of magnitude larger than the previous record. Because of the built-in programmability, this quantum memory can be adapted on demand for several functions. As example applications, we realize quantum queue, stack, and buffer which closely resemble the counterpart devices for classical information processing. We further demonstrate the storage and reshuffle of four entangled pairs of photonic pulses with probabilistic arrival time and arbitrary release order via the memory, which is an essential requirement for the realization of quantum repeaters and efficient routing in quantum networks. Realization of this multipurpose programmable quantum memory thus constitutes a key enabling building block for future large-scale fully functional quantum networks.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":null,"pages":null},"PeriodicalIF":12.5,"publicationDate":"2024-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140642735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-24DOI: 10.1103/physrevx.14.021017
Unai Muniain, Ruben Esteban, Javier Aizpurua, Jean-Jacques Greffet
A direct current through a metal-insulator-metal tunneling junction emits light when surface-plasmon polaritons (SPPs) are excited. Two distinct processes are believed to coexist in this light emission mediated by surface plasmons: inelastic tunneling, where electrons excite SPPs in the insulator gap, and hot-electron radiative decay, which occurs in the electrodes after elastic tunneling. Previous theoretical approaches to study light emission by inelastic tunneling have relied on Bardeen’s approximation where the electronic wave functions are considered only in the barrier of the junction. In this work, we introduce an extension to models of inelastic tunneling by incorporating the full quantum device solution of the Schrödinger equation, which can also account for processes in the metallic electrodes. The extension unveils the existence of long-range correlations of the current density across the barrier and enables us to establish the equivalence between two models widely used in the past: (i) a calculation of the inelastic transition rate between two states across the barrier based on Fermi’s golden rule and (ii) a calculation of the power transferred to plasmons by current fluctuations. Importantly, the new model accounts for processes that take place in the metallic electrodes and that could not be described within Bardeen’s approximation. Hence, it is no longer necessary to invoke a hot-electron mechanism to obtain a dependence on the geometry of metallic electrodes. The new framework enables to discuss the role of surface plasmons localized in different metal-insulator interfaces and to include possible nonlocal effects at the interfaces.
{"title":"Unified Treatment of Light Emission by Inelastic Tunneling: Interaction of Electrons and Photons beyond the Gap","authors":"Unai Muniain, Ruben Esteban, Javier Aizpurua, Jean-Jacques Greffet","doi":"10.1103/physrevx.14.021017","DOIUrl":"https://doi.org/10.1103/physrevx.14.021017","url":null,"abstract":"A direct current through a metal-insulator-metal tunneling junction emits light when surface-plasmon polaritons (SPPs) are excited. Two distinct processes are believed to coexist in this light emission mediated by surface plasmons: inelastic tunneling, where electrons excite SPPs in the insulator gap, and hot-electron radiative decay, which occurs in the electrodes after elastic tunneling. Previous theoretical approaches to study light emission by inelastic tunneling have relied on Bardeen’s approximation where the electronic wave functions are considered only in the barrier of the junction. In this work, we introduce an extension to models of inelastic tunneling by incorporating the full quantum device solution of the Schrödinger equation, which can also account for processes in the metallic electrodes. The extension unveils the existence of long-range correlations of the current density across the barrier and enables us to establish the equivalence between two models widely used in the past: (i) a calculation of the inelastic transition rate between two states across the barrier based on Fermi’s golden rule and (ii) a calculation of the power transferred to plasmons by current fluctuations. Importantly, the new model accounts for processes that take place in the metallic electrodes and that could not be described within Bardeen’s approximation. Hence, it is no longer necessary to invoke a hot-electron mechanism to obtain a dependence on the geometry of metallic electrodes. The new framework enables to discuss the role of surface plasmons localized in different metal-insulator interfaces and to include possible nonlocal effects at the interfaces.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":null,"pages":null},"PeriodicalIF":12.5,"publicationDate":"2024-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140640343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-23DOI: 10.1103/physrevx.14.021015
Maurizio Fagotti
A quantum spin- chain with an axial symmetry is normally described by quasiparticles associated with the spins oriented along the axis of rotation. Kinetic constraints can enrich such a description by setting apart different species of quasiparticles, which can get stuck at high enough density, realizing the quantum analog of jamming. We identify a family of interactions satisfying simple kinetic constraints and consider generic translationally invariant models built up from them. We study dynamics following a local unjamming perturbation in a jammed state. We show that they can be mapped into dynamics of ordinary unconstrained systems, but the nonlocality of the mapping changes the scales at which the phenomena manifest themselves. Scattering of quasiparticles, formation of bound states, and eigenstate localization become all visible at macroscopic scales. Depending on whether a symmetry is present or not, the microscopic details of the jammed state turn out to have either a marginal or a strong effect. In the former case or when the initial state is almost homogeneous, we show that even a product state is turned into a macroscopic quantum state.
{"title":"Quantum Jamming Brings Quantum Mechanics to Macroscopic Scales","authors":"Maurizio Fagotti","doi":"10.1103/physrevx.14.021015","DOIUrl":"https://doi.org/10.1103/physrevx.14.021015","url":null,"abstract":"A quantum spin-<math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mfrac><mn>1</mn><mn>2</mn></mfrac></math> chain with an axial symmetry is normally described by quasiparticles associated with the spins oriented along the axis of rotation. Kinetic constraints can enrich such a description by setting apart different species of quasiparticles, which can get stuck at high enough density, realizing the quantum analog of jamming. We identify a family of interactions satisfying simple kinetic constraints and consider generic translationally invariant models built up from them. We study dynamics following a local unjamming perturbation in a jammed state. We show that they can be mapped into dynamics of ordinary unconstrained systems, but the nonlocality of the mapping changes the scales at which the phenomena manifest themselves. Scattering of quasiparticles, formation of bound states, and eigenstate localization become all visible at macroscopic scales. Depending on whether a symmetry is present or not, the microscopic details of the jammed state turn out to have either a marginal or a strong effect. In the former case or when the initial state is almost homogeneous, we show that even a product state is turned into a macroscopic quantum state.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":null,"pages":null},"PeriodicalIF":12.5,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140640324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-23DOI: 10.1103/physrevx.14.021016
Dushko Kuzmanovski, Jonathan Schmidt, Nicola A. Spaldin, Henrik M. Rønnow, Gabriel Aeppli, Alexander V. Balatsky
Dynamical perturbations modify the states of classical systems in surprising ways and give rise to important applications in science and technology. For example, Floquet engineering exploits the possibility of band formation in the frequency domain when a strong, periodic variation is imposed on parameters such as spring constants. We describe here Kapitza engineering, where a drive field oscillating at a frequency much higher than the characteristic frequencies for the linear response of a system changes the potential energy surface so much that maxima found at equilibrium become local minima, in precise analogy to the celebrated Kapitza pendulum where the unstable inverted configuration, with the mass above rather than below the fulcrum, actually becomes stable. Our starting point is a quantum field theory of the Ginzburg-Devonshire type, suitable for many condensed matter systems, including particularly ferroelectrics and quantum paralectrics. We show that an off-resonance oscillatory electric field generated by a laser-driven terahertz source can induce ferroelectric order in the quantum-critical limit. Heating effects are estimated to be manageable using pulsed radiation; “hidden” radiation-induced order can persist to low temperatures without further pumping due to stabilization by strain. We estimate the Ginzburg-Devonshire free-energy coefficients in using density-functional theory and the stochastic self-consistent harmonic approximation accelerated by a machine-learned force field. Although we find that is not an optimal choice for Kapitza stabilization, we show that scanning for further candidate materials can be performed at the computationally convenient density-functional theory level. We suggest second harmonic generation, soft-mode spectroscopy, and x-ray diffraction experiments to characterize the induced order.
动态扰动以惊人的方式改变着经典系统的状态，并在科学和技术领域产生了重要的应用。例如，当对弹簧常数等参数施加强烈的周期性变化时，Floquet 工程学就利用了频域中频带形成的可能性。我们在这里描述的卡皮查工程学，是指以远高于系统线性响应特征频率的频率振荡的驱动场极大地改变了势能面，以至于平衡时的最大值变成了局部最小值，这与著名的卡皮查摆精确类比，在卡皮查摆中，质量在支点上方而非下方的不稳定倒置配置实际上变得稳定。我们的出发点是金兹伯格-德文郡类型的量子场论，它适用于许多凝聚态系统，尤其包括铁电和量子对偶。我们证明，由激光驱动的太赫兹源产生的非共振振荡电场可以在量子临界极限中诱导铁电有序。据估计，使用脉冲辐射可以控制加热效应；由于应变的稳定作用，"隐藏的 "辐射诱导有序可以持续到低温，而无需进一步抽运。我们使用密度函数理论和机器学习力场加速的随机自洽谐波近似来估算 SrTiO3 中的金兹堡-德文郡自由能系数。尽管我们发现 SrTiO3 并不是卡皮查稳定化的最佳选择，但我们表明，可以在计算方便的密度泛函理论水平上扫描更多候选材料。我们建议用二次谐波发生、软模光谱和 X 射线衍射实验来表征诱导阶。
{"title":"Kapitza Stabilization of Quantum Critical Order","authors":"Dushko Kuzmanovski, Jonathan Schmidt, Nicola A. Spaldin, Henrik M. Rønnow, Gabriel Aeppli, Alexander V. Balatsky","doi":"10.1103/physrevx.14.021016","DOIUrl":"https://doi.org/10.1103/physrevx.14.021016","url":null,"abstract":"Dynamical perturbations modify the states of classical systems in surprising ways and give rise to important applications in science and technology. For example, Floquet engineering exploits the possibility of band formation in the frequency domain when a strong, periodic variation is imposed on parameters such as spring constants. We describe here Kapitza engineering, where a drive field oscillating at a frequency much higher than the characteristic frequencies for the linear response of a system changes the potential energy surface so much that maxima found at equilibrium become local minima, in precise analogy to the celebrated Kapitza pendulum where the unstable inverted configuration, with the mass above rather than below the fulcrum, actually becomes stable. Our starting point is a quantum field theory of the Ginzburg-Devonshire type, suitable for many condensed matter systems, including particularly ferroelectrics and quantum paralectrics. We show that an off-resonance oscillatory electric field generated by a laser-driven terahertz source can induce ferroelectric order in the quantum-critical limit. Heating effects are estimated to be manageable using pulsed radiation; “hidden” radiation-induced order can persist to low temperatures without further pumping due to stabilization by strain. We estimate the Ginzburg-Devonshire free-energy coefficients in <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mtext>SrTiO</mtext><mn>3</mn></msub></math> using density-functional theory and the stochastic self-consistent harmonic approximation accelerated by a machine-learned force field. Although we find that <math display=\"inline\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mtext>SrTiO</mtext><mn>3</mn></msub></math> is not an optimal choice for Kapitza stabilization, we show that scanning for further candidate materials can be performed at the computationally convenient density-functional theory level. We suggest second harmonic generation, soft-mode spectroscopy, and x-ray diffraction experiments to characterize the induced order.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":null,"pages":null},"PeriodicalIF":12.5,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140640196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-19DOI: 10.1103/physrevx.14.021014
Fridtjof Brauns, M. Cristina Marchetti
In recent years, nonreciprocally coupled systems have received growing attention. Previous work has shown that the interplay of nonreciprocal coupling and Goldstone modes can drive the emergence of temporal order such as traveling waves. We show that these phenomena are generically found in a broad class of pattern-forming systems, including mass-conserving reaction-diffusion systems and viscoelastic active gels. All these systems share a characteristic dispersion relation that acquires a nonzero imaginary part at the edge of the band of unstable modes and exhibit a regime of propagating structures (traveling wave bands or droplets). We show that models for these systems can be mapped to a common “normal form” that can be seen as a spatially extended generalization of the FitzHugh-Nagumo model, providing a unifying dynamical-systems perspective. We show that the minimal nonreciprocal Cahn-Hilliard equations exhibit a surprisingly rich set of behaviors, including interrupted coarsening of traveling waves without selection of a preferred wavelength and transversal undulations of wave fronts in two dimensions. We show that the emergence of traveling waves and their speed are precisely predicted from the local dispersion relation at interfaces far away from the homogeneous steady state. Our work, thus, generalizes previously studied nonreciprocal phase transitions and shows that interfaces are the relevant collective excitations governing the rich dynamical patterns of conserved fields.
{"title":"Nonreciprocal Pattern Formation of Conserved Fields","authors":"Fridtjof Brauns, M. Cristina Marchetti","doi":"10.1103/physrevx.14.021014","DOIUrl":"https://doi.org/10.1103/physrevx.14.021014","url":null,"abstract":"In recent years, nonreciprocally coupled systems have received growing attention. Previous work has shown that the interplay of nonreciprocal coupling and Goldstone modes can drive the emergence of temporal order such as traveling waves. We show that these phenomena are generically found in a broad class of pattern-forming systems, including mass-conserving reaction-diffusion systems and viscoelastic active gels. All these systems share a characteristic dispersion relation that acquires a nonzero imaginary part at the edge of the band of unstable modes and exhibit a regime of propagating structures (traveling wave bands or droplets). We show that models for these systems can be mapped to a common “normal form” that can be seen as a spatially extended generalization of the FitzHugh-Nagumo model, providing a unifying dynamical-systems perspective. We show that the minimal nonreciprocal Cahn-Hilliard equations exhibit a surprisingly rich set of behaviors, including interrupted coarsening of traveling waves without selection of a preferred wavelength and transversal undulations of wave fronts in two dimensions. We show that the emergence of traveling waves and their speed are precisely predicted from the <i>local</i> dispersion relation at interfaces far away from the homogeneous steady state. Our work, thus, generalizes previously studied nonreciprocal phase transitions and shows that interfaces are the relevant collective excitations governing the rich dynamical patterns of conserved fields.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":null,"pages":null},"PeriodicalIF":12.5,"publicationDate":"2024-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140621459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-19DOI: 10.1103/physrevx.14.021013
Clemens Kuhlenkamp, Wilhelm Kadow, Ataç Imamoğlu, Michael Knap
We propose multilayer moiré structures in strong external magnetic fields as a novel platform for realizing highly tunable, frustrated Hubbard physics with topological order. Identifying the layer degree of freedom as a pseudospin allows us to retain SU(2) symmetry while controlling ring-exchange processes and concurrently quenching the kinetic energy by large external magnetic fields. This way, a broad class of interacting Hubbard-Hofstadter states and their transitions can be studied. Remarkably, in the limit of strong interactions the system becomes Mott insulating and we find chiral pseudospin-liquid phases which are induced by the magnetic field. We find that this topologically ordered state remains exceptionally stable toward relevant perturbations. We discuss how layer pseudospin can be probed in near-term experiments. As the magnetic flux can be easily tuned in moiré systems, our approach provides a promising route toward the experimental realization and control of topologically ordered phases of matter.
{"title":"Chiral Pseudospin Liquids in Moiré Heterostructures","authors":"Clemens Kuhlenkamp, Wilhelm Kadow, Ataç Imamoğlu, Michael Knap","doi":"10.1103/physrevx.14.021013","DOIUrl":"https://doi.org/10.1103/physrevx.14.021013","url":null,"abstract":"We propose multilayer moiré structures in strong external magnetic fields as a novel platform for realizing highly tunable, frustrated Hubbard physics with topological order. Identifying the layer degree of freedom as a pseudospin allows us to retain SU(2) symmetry while controlling ring-exchange processes and concurrently quenching the kinetic energy by large external magnetic fields. This way, a broad class of interacting Hubbard-Hofstadter states and their transitions can be studied. Remarkably, in the limit of strong interactions the system becomes Mott insulating and we find chiral pseudospin-liquid phases which are induced by the magnetic field. We find that this topologically ordered state remains exceptionally stable toward relevant perturbations. We discuss how layer pseudospin can be probed in near-term experiments. As the magnetic flux can be easily tuned in moiré systems, our approach provides a promising route toward the experimental realization and control of topologically ordered phases of matter.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":null,"pages":null},"PeriodicalIF":12.5,"publicationDate":"2024-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140621478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-16DOI: 10.1103/physrevx.14.021011
Hong-Yi Wang, Fei Song, Zhong Wang
The non-Hermitian skin effect dramatically reshapes the energy bands of non-Hermitian systems, meaning that the usual Bloch band theory is fundamentally inadequate as their characterization. The non-Bloch band theory, in which the concept of Brillouin zone is generalized, has been widely applied to investigate non-Hermitian systems in one spatial dimension. However, its generalization to higher dimensions has been challenging. Here, we develop a formulation of the non-Hermitian skin effect and non-Bloch band theory in arbitrary spatial dimensions, which is based on a natural geometrical object known as the amoeba. Our theory provides a general framework for studying non-Hermitian bands beyond one dimension. Key quantities of non-Hermitian bands, including the energy spectrum, eigenstates profiles, and the generalized Brillouin zone, can be efficiently obtained from this approach.
{"title":"Amoeba Formulation of Non-Bloch Band Theory in Arbitrary Dimensions","authors":"Hong-Yi Wang, Fei Song, Zhong Wang","doi":"10.1103/physrevx.14.021011","DOIUrl":"https://doi.org/10.1103/physrevx.14.021011","url":null,"abstract":"The non-Hermitian skin effect dramatically reshapes the energy bands of non-Hermitian systems, meaning that the usual Bloch band theory is fundamentally inadequate as their characterization. The non-Bloch band theory, in which the concept of Brillouin zone is generalized, has been widely applied to investigate non-Hermitian systems in one spatial dimension. However, its generalization to higher dimensions has been challenging. Here, we develop a formulation of the non-Hermitian skin effect and non-Bloch band theory in arbitrary spatial dimensions, which is based on a natural geometrical object known as the amoeba. Our theory provides a general framework for studying non-Hermitian bands beyond one dimension. Key quantities of non-Hermitian bands, including the energy spectrum, eigenstates profiles, and the generalized Brillouin zone, can be efficiently obtained from this approach.","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":null,"pages":null},"PeriodicalIF":12.5,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140603542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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