Showing papers on "Dissipative system published in 2016"
TL;DR: The concept of parity-time symmetric systems is rooted in non-Hermitian quantum mechanics where complex potentials obeying this symmetry could exhibit real spectra as discussed by the authors, which has applications in many fields of physics, e.g., in optics, metamaterials, acoustics, Bose-Einstein condensation, electronic circuitry, etc.
Abstract: The concept of parity-time symmetric systems is rooted in non-Hermitian quantum mechanics where complex potentials obeying this symmetry could exhibit real spectra. The concept has applications in many fields of physics, e.g., in optics, metamaterials, acoustics, Bose-Einstein condensation, electronic circuitry, etc. The inclusion of nonlinearity has led to a number of new phenomena for which no counterparts exist in traditional dissipative systems. Several examples of nonlinear parity-time symmetric systems in different physical disciplines are presented and their implications discussed.
938 citations
TL;DR: A nonlinear soft system that is able to propagate large-amplitude signals over arbitrary distances without any signal degradation is demonstrated, made use of bistable beams to store and then release elastic energy along the path of the wave, balancing both dissipative and dispersive effects.
Abstract: Soft structures with rationally designed architectures capable of large, nonlinear deformation present opportunities for unprecedented, highly tunable devices and machines. However, the highly dissipative nature of soft materials intrinsically limits or prevents certain functions, such as the propagation of mechanical signals. Here we present an architected soft system composed of elastomeric bistable beam elements connected by elastomeric linear springs. The dissipative nature of the polymer readily damps linear waves, preventing propagation of any mechanical signal beyond a short distance, as expected. However, the unique architecture of the system enables propagation of stable, nonlinear solitary transition waves with constant, controllable velocity and pulse geometry over arbitrary distances. Because the high damping of the material removes all other linear, small-amplitude excitations, the desired pulse propagates with high fidelity and controllability. This phenomenon can be used to control signals, as demonstrated by the design of soft mechanical diodes and logic gates.
262 citations
TL;DR: In this paper, the irregularity factors for a self-gravitating spherical star evolving in the presence of an imperfect fluid were investigated for particular cases of dust and isotropic and anisotropic fluids in dissipative and nondissipative regimes in the framework of gravity.
Abstract: We investigate irregularity factors for a self-gravitating spherical star evolving in the presence of an imperfect fluid. We explore the gravitational field equations and the dynamical equations with the systematic construction in $f(R,T)$ gravity, where $T$ is the trace of the energy-momentum tensor. Furthermore, we analyze two well-known differential equations (which occupy principal importance in the exploration of causes of energy density inhomogeneities) with the help of the Weyl tensor and the conservation laws. The irregularity factors for a spherical star are examined for particular cases of dust and isotropic and anisotropic fluids in dissipative and nondissipative regimes in the framework of $f(R,T)$ gravity. It is found that, as the complexity of the matter with the anisotropic stresses increases, the inhomogeneity factor corresponds more closely to one of the structure scalars.
222 citations
TL;DR: In this paper, a one-dimensional chain of 72 microwave cavities, coupled to a superconducting qubit, was used to coherently drive the system into a nonequilibrium steady state.
Abstract: Condensed matter physics has been driven forward by significant experimental and theoretical progress in the study and understanding of equilibrium phase transitions based on symmetry and topology. However, nonequilibrium phase transitions have remained a challenge, in part due to their complexity in theoretical descriptions and the additional experimental difficulties in systematically controlling systems out of equilibrium. Here, we study a one-dimensional chain of 72 microwave cavities, each coupled to a superconducting qubit, and coherently drive the system into a nonequilibrium steady state. We find experimental evidence for a dissipative phase transition in the system in which the steady state changes dramatically as the mean photon number is increased. Near the boundary between the two observed phases, the system demonstrates bistability, with characteristic switching times as long as 60 ms -- far longer than any of the intrinsic rates known for the system. This experiment demonstrates the power of circuit QED systems for studying nonequilibrium condensed matter physics and paves the way for future experiments exploring nonequilbrium physics with many-body quantum optics.
183 citations
TL;DR: A driven-dissipative Josephson junction array realized with a weakly interacting Bose-Einstein condensate residing in a one-dimensional optical lattice is experimentally studied, finding a critical slowing down, indicating the presence of a nonequilibrium phase transition.
Abstract: We experimentally study a driven-dissipative Josephson junction array, realized with a weakly interacting Bose-Einstein condensate residing in a one-dimensional optical lattice. Engineered losses on one site act as a local dissipative process, while tunneling from the neighboring sites constitutes the driving force. We characterize the emerging steady states of this atomtronic device. With increasing dissipation strength γ the system crosses from a superfluid state, characterized by a coherent Josephson current into the lossy site, to a resistive state, characterized by an incoherent hopping transport. For intermediate values of γ, the system exhibits bistability, where a superfluid and an incoherent branch coexist. We also study the relaxation dynamics towards the steady state, where we find a critical slowing down, indicating the presence of a nonequilibrium phase transition.
173 citations
TL;DR: In this article, an elastic metamaterial with multiple dissipative resonators is presented for broadband wave mitigation by properly utilizing interactions from resonant motions and viscoelastic effects of the constitutive material.
168 citations
TL;DR: In this paper, the authors derived the microscopic optomagnonic Hamiltonian of a macrospin in the optical cavities and showed that the induced dissipation coefficient can change sign on the Bloch sphere, leading to self-sustained oscillations.
Abstract: Experiments during the past 2 years have shown strong resonant photon-magnon coupling in microwave cavities, while coupling in the optical regime was demonstrated very recently for the first time. Unlike with microwaves, the coupling in optical cavities is parametric, akin to optomechanical systems. This line of research promises to evolve into a new field of optomagnonics, aimed at the coherent manipulation of elementary magnetic excitations in solid-state systems by optical means. In this work we derive the microscopic optomagnonic Hamiltonian. In the linear regime the system reduces to the well-known optomechanical case, with remarkably large coupling. Going beyond that, we study the optically induced nonlinear classical dynamics of a macrospin. In the fast-cavity regime we obtain an effective equation of motion for the spin and show that the light field induces a dissipative term reminiscent of Gilbert damping. The induced dissipation coefficient, however, can change sign on the Bloch sphere, giving rise to self-sustained oscillations. When the full dynamics of the system is considered, the system can enter a chaotic regime by successive period doubling of the oscillations.
147 citations
TL;DR: In this article, a theory is developed to analytically represent a general class of driven-dissipative nonlinear resonators, which allows one to reveal the mesoscopic regime of interacting photons and dissipative phase transitions.
Abstract: A theory is developed to analytically represent a general class of driven-dissipative nonlinear resonators. The solvable model allows one to reveal the mesoscopic regime of interacting photons and dissipative phase transitions.
137 citations
TL;DR: In this paper, the key role of short-range fluctuations in dissipative phase transitions is theoretically demonstrated and can be experimentally reproduced in the future using trapped ions, Rydberg states of atoms, or microwave circuits.
Abstract: Phase transitions are ubiquitous in nature and can occur in out-of-equilibrium situations. The key role of short-range fluctuations in dissipative phase transitions is theoretically demonstrated and can be experimentally reproduced in the future using trapped ions, Rydberg states of atoms, or microwave circuits.
127 citations
TL;DR: In this article, the existence of continuous periodic weak solutions v of the Euler equations that do not conserve the kinetic energy and belong to the space Lt1(Cx1/3−e) was shown.
Abstract: For any ɛ > 0 we show the existence of continuous periodic weak solutions v of the Euler equations that do not conserve the kinetic energy and belong to the space Lt1(Cx1/3−e); namely, x ↦ v (x,t) is ⅓−e-Holder continuous in space at a.e. time t and the integral ∫[ υ(⋅,t) ]1/3−edt is finite. A well-known open conjecture of L. Onsager claims that such solutions exist even in the class Lt∞(Cx1/3−e).© 2016 Wiley Periodicals, Inc.
125 citations
TL;DR: In this article, the wave attenuation performance of dissipative solid acoustic metamaterials (AMMs) with local resonators possessing subwavelength band gaps is investigated, and the authors show that if the matrix material is slightly damped, it can be modeled as linear elastic without the loss of accuracy given the resonator coating is dissipative.
Abstract: This paper studies the wave attenuation performance of dissipative solid acoustic metamaterials (AMMs) with local resonators possessing subwavelength band gaps. The metamaterial is composed of dense rubber-coated inclusions of a circular shape embedded periodically in a matrix medium. Visco-elastic material losses present in a matrix and/or resonator coating are introduced by either the Kelvin–Voigt or generalized Maxwell models. Numerical solutions are obtained in the frequency domain by means of k ( ω ) -approach combined with the finite element method. Spatially attenuating waves are described by real frequencies ω and complex-valued wave vectors k . Complete 3D band structure diagrams including complex-valued pass bands are evaluated for the undamped linear elastic and several visco-elastic AMM cases. The changes in the band diagrams due to the visco-elasticity are discussed in detail; the comparison between the two visco-elastic models representing artificial (Kelvin–Voigt model) and experimentally characterized (generalized Maxwell model) damping is performed. The interpretation of the results is facilitated by using attenuation and transmission spectra. Two mechanisms of the energy absorption, i.e. due to the resonance of the inclusions and dissipative effects in the materials, are discussed separately. It is found that the visco-elastic damping of the matrix material decreases the attenuation performance of AMMs within band gaps; however, if the matrix material is slightly damped, it can be modeled as linear elastic without the loss of accuracy given the resonator coating is dissipative. This study also demonstrates that visco-elastic losses properly introduced in the resonator coating improve the attenuation bandwidth of AMMs although the attenuation on the resonance peaks is reduced.
TL;DR: In this paper, a new concept of dissipative measure-valued solution to the compressible Navier-Stokes system satisfying a relevant form of the total energy balance is introduced.
Abstract: We introduce a new concept of dissipative measure-valued solution to the compressible Navier–Stokes system satisfying, in addition, a relevant form of the total energy balance. Then we show that a dissipative measure-valued and a standard smooth classical solution originating from the same initial data coincide (weak-strong uniqueness principle) as long as the latter exists. Such a result facilitates considerably the proof of convergence of solutions to various approximations including certain numerical schemes that are known to generate a measure-valued solution. As a byproduct we show that any measure-valued solution with bounded density component that starts from smooth initial data is necessarily a classical one.
TL;DR: This work considers two different types of dissipation relevant to systems of ultracold atoms: dephasing due to inelastic scattering on the lattice lasers and particle loss, and their different effects in the limiting cases of weak and strong interactions.
Abstract: Coupling a many-body-localized system to a dissipative bath necessarily leads to delocalization. Here, we investigate the nature of the ensuing relaxation dynamics and the information it holds on the many-body-localized state. We formulate the relevant Lindblad equation in terms of the local integrals of motion of the underlying localized Hamiltonian. This allows us to map the quantum evolution deep in the localized state to tractable classical rate equations. We consider two different types of dissipation relevant to systems of ultracold atoms: dephasing due to inelastic scattering on the lattice lasers and particle loss. Our approach allows us to characterize their different effects in the limiting cases of weak and strong interactions.
TL;DR: By combining local spontaneous emission with coherent couplings, the engineer many-body dissipation that drives the system from an arbitrary initial state into a Greenberger-Horne-Zeilinger state and demonstrates that using the technique highly entangled steady states can be prepared efficiently in a time that scales polynomially with the system size.
Abstract: We present a technique for the dissipative preparation of highly entangled multiparticle states of atoms coupled to common oscillator modes. By combining local spontaneous emission with coherent couplings, we engineer many-body dissipation that drives the system from an arbitrary initial state into a Greenberger-Horne-Zeilinger state. We demonstrate that using our technique highly entangled steady states can be prepared efficiently in a time that scales polynomially with the system size. Our protocol assumes generic couplings and will thus enable the dissipative production of multiparticle entanglement in a wide range of physical systems. As an example, we demonstrate the feasibility of our scheme in state-of-the-art trapped-ion systems.
TL;DR: The time-dependent energy transfer in a driven quantum system strongly coupled to a heat bath is studied within an influence functional approach and it is shown that the energy flows obey a balance relation, and that, for strong coupling, the interaction may constitute the major dissipative channel.
Abstract: The time-dependent energy transfer in a driven quantum system strongly coupled to a heat bath is studied within an influence functional approach. Exact formal expressions for the statistics of energy dissipation into the different channels are derived. The general method is applied to the driven dissipative two-state system. It is shown that the energy flows obey a balance relation, and that, for strong coupling, the interaction may constitute the major dissipative channel. Results in analytic form are presented for the particular value K=1/2 of strong Ohmic dissipation. The energy flows show interesting behaviors including driving-induced coherences and quantum stochastic resonances. It is found that the general characteristics persists for K near 1/2.
TL;DR: In this paper, small-scale structure in the context of dissipative dark matter was studied in models with a hidden unbroken Abelian sector, so that dark matter couples to a massless dark photosphere.
Abstract: Small-scale structure is studied in the context of dissipative dark matter, arising for instance in models with a hidden unbroken Abelian sector, so that dark matter couples to a massless dark phot ...
TL;DR: In this article, an efficient many-body algorithm for simulating open quantum system dynamics that utilizes a time-dependent variational principle for matrix product states to evolve large system-environment states is presented.
Abstract: We report the development of an efficient many-body algorithm for simulating open quantum system dynamics that utilizes a time-dependent variational principle for matrix product states to evolve large system-environment states. Capturing all system-environment correlations, we reproduce the nonperturbative, quantum-critical dynamics of the zero-temperature spin-boson model, and then exploit the many-body information to visualize the complete time-frequency spectrum of the environmental excitations. Our ``environmental spectra'' reveal correlated vibrational motion in polaronic modes which preserve their vibrational coherence during incoherent spin relaxation, demonstrating how environment information could yield valuable insights into complex quantum dissipative processes.
TL;DR: In this paper, the existence of multiple nonequilibrium steady states in a coherently driven $XY$ lattice of dissipative two-level systems is investigated, and a circuit QED quantum simulator implementable with current technology is proposed.
Abstract: In the present work we investigate the existence of multiple nonequilibrium steady states in a coherently driven $XY$ lattice of dissipative two-level systems. A commonly used mean-field ansatz, in which spatial correlations are neglected, predicts a bistable behavior with a sharp shift between low- and high-density states. In contrast one-dimensional matrix product methods reveal these effects to be artifacts of the mean-field approach, with both disappearing once correlations are taken fully into account. Instead, a bunching-antibunching transition emerges. This indicates that alternative approaches should be considered for higher spatial dimensions, where classical simulations are currently infeasible. Thus we propose a circuit QED quantum simulator implementable with current technology to enable an experimental investigation of the model considered.
TL;DR: The proposed mathematical representation can be useful to understand electrochemical phenomena, propagation of energy in dissipative systems, irreversible thermodynamics, quantum optics or turbulent diffusion, thermal stresses, models of porous electrodes, the description of gel solvents and anomalous complex processes.
TL;DR: In this article, a universal set of one and two-qubit gates within the decoherence free subspaces (DFSs) of an ensemble of two-level atom-like systems is proposed.
Abstract: The interaction of quantum emitters with one-dimensional photon-like reservoirs induces strong and long-range dissipative couplings that give rise to the emergence of the so-called decoherence free subspaces (DFSs) which are decoupled from dissipation. When introducing weak perturbations on the emitters, e.g., driving, the strong collective dissipation enforces an effective coherent evolution within the DFS. In this work, we show explicitly how by introducing single-site resolved drivings, we can use the effective dynamics within the DFS to design a universal set of one and two-qubit gates within the DFS of an ensemble of two-level atom-like systems. Using Liouvillian perturbation theory we calculate the scaling with the relevant figures of merit of the systems, such as the Purcell factor and imperfect control of the drivings. Finally, we compare our results with previous proposals using atomic Λ systems in leaky cavities.
TL;DR: In this paper, a polaron transformed Redfield equation (PTRE) was proposed to calculate the non-equilibrium steady states in the intermediate coupling regime, in which Fermi's golden rule will fail.
Abstract: The concept of polaron, emerged from condense matter physics, describes the dynamical interaction of moving particle with its surrounding bosonic modes. This concept has been developed into a useful method to treat open quantum systems with a complete range of system-bath coupling strength. Especially, the polaron transformation approach shows its validity in the intermediate coupling regime, in which the Redfield equation or Fermi’s golden rule will fail. In the polaron frame, the equilibrium distribution carried out by perturbative expansion presents a deviation from the canonical distribution, which is beyond the usual weak coupling assumption in thermodynamics. A polaron transformed Redfield equation (PTRE) not only reproduces the dissipative quantum dynamics but also provides an accurate and efficient way to calculate the non-equilibrium steady states. Applications of the PTRE approach to problems such as exciton diffusion, heat transport and light-harvesting energy transfer are presented.
TL;DR: In this article, an abstract method for deriving decay estimates on the semigroup associated to non-symmetric operators in Banach spaces is presented. But the authors do not consider the shrinkage of the functional space.
Abstract: The aim of the present paper is twofold:
1.
We carry on with developing an abstract method for deriving decay estimates on the semigroup associated to non-symmetric operators in Banach spaces as introduced in [10]. We extend the method so as to consider the shrinkage of the functional space. Roughly speaking, we consider a class of operators written as a dissipative part plus a mild perturbation, and we prove that if the associated semigroup satisfies a decay estimate in some reference space then it satisfies the same decay estimate in another—smaller or larger—Banach space under the condition that a certain iterate of the “mild perturbation” part of the operator combined with the dissipative part of the semigroup maps the larger space to the smaller space in a bounded way. The cornerstone of our approach is a factorization argument, reminiscent of the Dyson series.
2.
We apply this method to the kinetic Fokker-Planck equation when the spatial domain is either the torus with periodic boundary conditions, or the whole space with a confinement potential. We then obtain spectral gap estimates for the associated semigroup for various metrics, including Lebesgue norms, negative Sobolev norms, and the Monge-Kantorovich-Wasserstein distance W1.
TL;DR: In this paper, a universal Schwinger-Keldysh effective theory was proposed to describe macroscopic thermal fluctuations of a relativistic field theory with a doubling of degrees of freedom, an emergent abelian symmetry associated with entropy, and a topological supersymmetry.
Abstract: We outline a universal Schwinger-Keldysh effective theory which describes macroscopic thermal fluctuations of a relativistic field theory. The basic ingredients of our construction are three: a doubling of degrees of freedom, an emergent abelian symmetry associated with entropy, and a topological (BRST) supersymmetry imposing fluctuationdissipation theorem. We illustrate these ideas for a non-linear viscous fluid, and demonstrate that the resulting effective action obeys a generalized fluctuation-dissipation theorem, which guarantees a local form of the second law.
TL;DR: In this paper, a tensor network algorithm was proposed to simulate 2D quantum lattice dissipative systems in the thermodynamic limit, based on the intuition that strong dissipation kills quantum entanglement before it gets too large to handle.
Abstract: Understanding dissipation in 2D quantum many-body systems is a remarkably difficult open challenge. Here we show how numerical simulations for this problem are possible by means of a tensor network algorithm that approximates steady-states of 2D quantum lattice dissipative systems in the thermodynamic limit. Our method is based on the intuition that strong dissipation kills quantum entanglement before it gets too large to handle. We test its validity by simulating a dissipative quantum Ising model, relevant for dissipative systems of interacting Rydberg atoms, and benchmark our simulations with a variational algorithm based on product and correlated states. Our results support the existence of a first order transition in this model, with no bistable region. We also simulate a dissipative spin-1/2 XYZ model, showing that there is no re-entrance of the ferromagnetic phase. Our method enables the computation of steady states in 2D quantum lattice systems.
TL;DR: In this article, the dissipative interaction in an optical microcavity of high quality factor allows the detection of single nanoparticles, even when the real part of an analyte's polarizability approaches zero.
Abstract: Ultrasensitive detection of nanoscale particles has applications in important fields ranging from environmental monitoring to analysis of viral structures. The authors show that the dissipative interaction in an optical microcavity of high quality factor allows the detection of single nanoparticles, even when the real part of an analyte's polarizability approaches zero. This innovative approach presents a significant step towards practical optical sensors for use in physics, analytical chemistry, environmental science, and molecular biology.
TL;DR: In this paper, the coefficients of conservative and dissipative nonlinearities of a single-mode vibration of symmetric micromechanical resonators were derived from the ringdown response.
Abstract: We present a technique for estimation of the model parameters for a single-mode vibration of symmetric micromechanical resonators, including the coefficients of conservative and dissipative nonlinearities. The nonlinearities result in an amplitude-dependent frequency and a nonexponential decay, which are characterized from the ringdown response. An analysis of the amplitude of the ringdown response allows one to estimate the linear damping constant and the dissipative nonlinearity, and the zero-crossing points in the ringdown measurement can be used for characterization of the linear natural frequency and the Duffing and quintic nonlinearities of the vibrational mode, which arise from a combination of mechanical and electrostatic effects. [2015-0263]
TL;DR: In this paper, two error correction methods can be integrated in a nested feedback protocol to obtain the best properties of both error correction and error correction in quantum computation, and an experiment was conducted to show that two such methods can both be used in the same feedback protocol.
Abstract: Error correction by feedback is crucial in quantum computation, and an experiment now shows that two such methods can be integrated in a nested feedback protocol to obtain the best properties of both.
TL;DR: In this paper, the authors analyze the time-resolved energy transport and the entropy production in ac-driven quantum coherent electron systems coupled to multiple reservoirs at finite temperature, and show the importance of the energy stored in the contact and central regions for the second law of thermodynamics to be instantaneously satisfied.
Abstract: We analyze the time-resolved energy transport and the entropy production in ac-driven quantum coherent electron systems coupled to multiple reservoirs at finite temperature. At slow driving, we formulate the first and second laws of thermodynamics valid at each instant of time. We identify heat fluxes flowing through the different pieces of the device and emphasize the importance of the energy stored in the contact and central regions for the second law of thermodynamics to be instantaneously satisfied. In addition, we discuss conservative and dissipative contributions to the heat flux and to the entropy production as a function of time. We illustrate these ideas with a simple model corresponding to a driven level coupled to two reservoirs with different chemical potentials.
TL;DR: In this paper, anisotropic dissipative fluid dynamics is derived from the Boltzmann equation in terms of an expansion around a single-particle distribution function which is in local thermodynamical equilibrium, i.e., isotropic in momentum space.
Abstract: Fluid-dynamical equations of motion can be derived from the Boltzmann equation in terms of an expansion around a single-particle distribution function which is in local thermodynamical equilibrium, i.e., isotropic in momentum space in the rest frame of a fluid element. However, in situations where the single-particle distribution function is highly anisotropic in momentum space, such as the initial stage of heavy-ion collisions at relativistic energies, such an expansion is bound to break down. Nevertheless, one can still derive a fluid-dynamical theory, called anisotropic dissipative fluid dynamics, in terms of an expansion around a single-particle distribution function, ${\stackrel{^}{f}}_{0\mathbf{k}}$, which incorporates (at least parts of) the momentum anisotropy via a suitable parametrization. We construct such an expansion in terms of polynomials in energy and momentum in the direction of the anisotropy and of irreducible tensors in the two-dimensional momentum subspace orthogonal to both the fluid velocity and the direction of the anisotropy. From the Boltzmann equation we then derive the set of equations of motion for the irreducible moments of the deviation of the single-particle distribution function from ${\stackrel{^}{f}}_{0\mathbf{k}}$. Truncating this set via the 14-moment approximation, we obtain the equations of motion of anisotropic dissipative fluid dynamics.
TL;DR: In this article, the steady state of a driven-dissipative resonator subject to engineered two-photon processes was analyzed and the authors showed that the unique steady state is a statistical mixture of two cat-like states with opposite parity, in spite of significant onephoton losses.
Abstract: In quantum optics, photonic Schrodinger cats are superpositions of two coherent states with opposite phases and with a significant number of photons. Recently, these states have been observed in the transient dynamics of driven-dissipative resonators subject to engineered two-photon processes. Here we present an exact analytical solution of the steady-state density matrix for this class of systems, including one-photon losses, which are considered detrimental for the achievement of cat states. We demonstrate that the unique steady state is a statistical mixture of two cat-like states with opposite parity, in spite of significant one-photon losses. The transient dynamics to the steady state depends dramatically on the initial state and can pass through a metastable regime lasting orders of magnitudes longer than the photon lifetime. By considering individual quantum trajectories in photon-counting configuration, we find that the system intermittently jumps between two cats. Finally, we propose and study a feedback protocol based on this behaviour to generate a pure cat-like steady state.