scholarly journals Two-level systems coupled to Graphene plasmons: A Lindblad equation approach

2021 ◽  
pp. 2130007
Author(s):  
T. V. C. Antão ◽  
N. M. R. Peres
Keyword(s):  
Graphene Sheet ◽  
Quantum Electrodynamics ◽  
Open Quantum Systems ◽  
Thermal Bath ◽  
Quantization Scheme ◽  
Lindblad Equation ◽  
Dielectric Media ◽  
Two Level Systems ◽  
Schrodinger Cat State ◽  
Infinite Linear

In this paper, we review the theory of open quantum systems and macroscopic quantum electrodynamics, providing a self-contained account of many aspects of these two theories. The former is presented in the context of a qubit coupled to a electromagnetic thermal bath, the latter is presented in the context of a quantization scheme for surface-plasmon polaritons (SPPs) in graphene based on Langevin noise currents. This includes a calculation of the dyadic Green’s function (in the electrostatic limit) for a Graphene sheet between two semi-infinite linear dielectric media, and its subsequent application to the construction of SPP creation and annihilation operators. We then bring the two fields together and discuss the entanglement of two qubits in the vicinity of a graphene sheet which supports SPPs. The two qubits communicate with each other via the emission and absorption of SPPs. We find that a Schrödinger cat state involving the two qubits can be partially protected from decoherence by taking advantage of the dissipative dynamics in graphene. A comparison is also drawn between the dynamics at zero temperature, obtained via Schrödinger’s equation, and at finite temperature, obtained using the Lindblad equation.

Geometric phase for a two-level atom immersed in a thermal bath in the global monopole space–time

2019 ◽  
Vol 34 (03n04) ◽  
pp. 1950023 ◽  
Author(s):  
Zhi Wang ◽  
Huabing Cai ◽  
Chang Xu
Keyword(s):  
Geometric Phase ◽  
Thermal Environment ◽  
Open Quantum Systems ◽  
Thermal Fluctuation ◽  
Space Time ◽  
Thermal Bath ◽  
Massless Scalar ◽  
Massless Scalar Field ◽  
Global Monopole ◽  
Level Atom

In the framework of open quantum systems, and combining with the quantum field theory in curved space–time, we study the geometric phase for a static two-level atom immersed in a thermal bath of a massless scalar field in the background of global monopole space–time. We show that the correction to geometric phase of the atom results from combined effects of both thermal radiation of the thermal bath at finite temperature and the topological property of global monopole. We also discuss the modified geometric phases for this two-level atom purely due to thermal fluctuation of the thermal bath at an effective temperature in Minkowski space–time and also purely resulting from the effect of global monopole space–time. In addition, the numerical results of correction to the geometric phase induced by the effects of thermal environment and the global monopole is presented and discussed. It is clearly seen that the corrections depend crucially on the temperature T of environment and the position r of the atom relative to the global monopole.

scholarly journals IBM Q Experience as a versatile experimental testbed for simulating open quantum systems

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Guillermo García-Pérez ◽  
Matteo A. C. Rossi ◽  
Sabrina Maniscalco
Keyword(s):  
Quantum Electrodynamics ◽  
Quantum Physics ◽  
Open Quantum Systems ◽  
Cavity Quantum Electrodynamics ◽  
Quantum Systems ◽  
Entangled State ◽  
Specific Class ◽  
Linear Optics ◽  
Open Quantum ◽  
State Generation

AbstractThe advent of noisy intermediate-scale quantum (NISQ) technology is changing rapidly the landscape and modality of research in quantum physics. NISQ devices, such as the IBM Q Experience, have very recently proven their capability as experimental platforms accessible to everyone around the globe. Until now, IBM Q Experience processors have mostly been used for quantum computation and simulation of closed systems. Here, we show that these devices are also able to implement a great variety of paradigmatic open quantum systems models, hence providing a robust and flexible testbed for open quantum systems theory. During the last decade an increasing number of experiments have successfully tackled the task of simulating open quantum systems in different platforms, from linear optics to trapped ions, from nuclear magnetic resonance (NMR) to cavity quantum electrodynamics. Generally, each individual experiment demonstrates a specific open quantum system model, or at most a specific class. Our main result is to prove the great versatility of the IBM Q Experience processors. Indeed, we experimentally implement one and two-qubit open quantum systems, both unital and non-unital dynamics, Markovian and non-Markovian evolutions. Moreover, we realise proof-of-principle reservoir engineering for entangled state generation, demonstrate collisional models, and verify revivals of quantum channel capacity and extractable work, caused by memory effects. All these results are obtained using IBM Q Experience processors publicly available and remotely accessible online.

THE HARMONIC BALANCE TECHNIQUE ANALYSIS OF OPEN QUANTUM SYSTEMS

2008 ◽  
Vol 18 (07) ◽  
pp. 1973-1982
Author(s):  
PIER PAOLO CIVALLERI ◽  
MARCO GILLI ◽  
MICHELE BONNIN
Keyword(s):  
Electromagnetic Wave ◽  
Harmonic Balance ◽  
Linear Time ◽  
Open Quantum Systems ◽  
Quantum Systems ◽  
Thermal Bath ◽  
Fixed Temperature ◽  
Balance Technique ◽  
Harmonic Balance Technique ◽  
Steady State Performance

The Harmonic Balance Technique (HBT) is used to analyze the steady state performance of a two-state quantum system interacting with a classical sinusoidal electromagnetic wave and with a thermal bath at a fixed temperature. The linear time-variant differential equations describing such a system can be solved to any number of harmonics and the results can be compared with those obtained with the classical RWA approximation, thus emphasizing the validity limits of the latter.

scholarly journals Generation of Quantum Correlations in Bipartite Gaussian Open Quantum Systems

2018 ◽  
Vol 173 ◽  
pp. 01006 ◽  
Author(s):  
Aurelian Isar
Keyword(s):  
Open Systems ◽  
Thermal Environment ◽  
Open Quantum Systems ◽  
Quantum Correlations ◽  
Quantum Systems ◽  
Thermal Bath ◽  
Initial State ◽  
Entanglement Generation ◽  
Strength Of Interaction ◽  
Zero Values

We describe the generation of quantum correlations (entanglement, discord and steering) in a system composed of two coupled non-resonant bosonic modes immersed in a common thermal reservoir, in the framework of the theory of open systems. We show that for separable initial squeezed thermal states entanglement generation may take place, for definite values of squeezing parameter, average photon numbers, temperature of the thermal bath, dissipation constant and strength of interaction between the two bosonic modes. We also show that for initial uni-modal squeezed states Gaussian discord can be generated for all non-zero values of the strength of interaction between the modes. Likewise, for an initial separable state, a generation of Gaussian steering may take place temporarily, for definite values of the parameters characterizing the initial state and the thermal environment, and the strength of coupling between the two modes.

scholarly journals Dynamics of Open Quantum Systems I, Oscillation and Decay

Quantum ◽  
2022 ◽  
Vol 6 ◽  
pp. 615 ◽  
Author(s):  
Marco Merkli
Keyword(s):  
Main Part ◽  
Open Quantum Systems ◽  
Companion Paper ◽  
Quantum Systems ◽  
Thermal Bath ◽  
Coupling Constant ◽  
Level System ◽  
Concrete Case ◽  
Finite Dimensional ◽  
Characteristic Features

We develop a framework to analyze the dynamics of a finite-dimensional quantum system S in contact with a reservoir R. The full, interacting SR dynamics is unitary. The reservoir has a stationary state but otherwise dissipative dynamics. We identify a main part of the full dynamics, which approximates it for small values of the SR coupling constant, uniformly for all times t≥0. The main part consists of explicit oscillating and decaying parts. We show that the reduced system evolution is Markovian for all times. The technical novelty is a detailed analysis of the link between the dynamics and the spectral properties of the generator of the SR dynamics, based on Mourre theory. We allow for SR interactions with little regularity, meaning that the decay of the reservoir correlation function only needs to be polynomial in time, improving on the previously required exponential decay.In this work we distill the structural and technical ingredients causing the characteristic features of oscillation and decay of the SR dynamics. In the companion paper [27] we apply the formalism to the concrete case of an N-level system linearly coupled to a spatially infinitely extended thermal bath of non-interacting Bosons.

Interpolation of matrices and matrix-valued densities: The unbalanced case

2018 ◽  
Vol 30 (3) ◽  
pp. 458-480 ◽  
Author(s):  
YONGXIN CHEN ◽  
TRYPHON T. GEORGIOU ◽  
ALLEN TANNENBAUM
Keyword(s):  
Open Quantum Systems ◽  
Wasserstein Distance ◽  
Quantum Systems ◽  
Quantum Mechanical ◽  
Frobenius Norm ◽  
Spatial Dependency ◽  
Lindblad Equation ◽  
Optimal Mass Transport ◽  
Mechanical Formulation ◽  
The Matrix

We propose unbalanced versions of the quantum mechanical version of optimal mass transport that is based on the Lindblad equation describing open quantum systems. One of them is a natural interpolation framework between matrices and matrix-valued measures via a quantum mechanical formulation of Fisher-Rao information and the matricial Wasserstein distance, and the second is an interpolation between Wasserstein distance and Frobenius norm. We also give analogous results for the matrix-valued density measures, i.e., we add a spatial dependency on the density matrices. This might extend the applications of the framework to interpolating matrix-valued densities/images with unequal masses.

scholarly journals Entanglement dynamics for Unruh-DeWitt detectors interacting with massive scalar fields: the Unruh and anti-Unruh effects

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Yuebing Zhou ◽  
Jiawei Hu ◽  
Hongwei Yu
Keyword(s):  
Time Delay ◽  
Quantum System ◽  
Open Quantum Systems ◽  
Scalar Fields ◽  
Thermal Bath ◽  
Unruh Effect ◽  
Massive Scalar ◽  
Entanglement Dynamics ◽  
The One ◽  
Time Delay Effect

Abstract We study, in the framework of open quantum systems, the entanglement dynamics for a quantum system composed of two uniformly accelerated Unruh-Dewitt detectors interacting with a bath of massive scalar fields in the Minkowski vacuum. We find that the entanglement evolution for the quantum system coupled with massive fields is always slower compared with that of the one coupled with massless fields, and this time-delay effect brought about by the field being massive can however be counteracted by a large enough acceleration, in contrast to the case of a static quantum system in a thermal bath, where this time delay is not affected by the temperature. Remarkably, the maximal concurrence of the quantum system generated during evolution may increase with acceleration for any inter-detector separation while that for static ones in a thermal bath decreases monotonically with temperature, and this can be considered as an anti-Unruh effect in terms of the entanglement generated.

scholarly journals Parity-Assisted Generation of Nonclassical States of Light in Circuit Quantum Electrodynamics

Symmetry ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 372 ◽  
Author(s):  
Francisco Cárdenas-López ◽  
Guillermo Romero ◽  
Lucas Lamata ◽  
Enrique Solano ◽  
Juan Retamal
Keyword(s):  
Quantum Electrodynamics ◽  
Random Number Generator ◽  
Nonclassical States ◽  
Circuit Quantum Electrodynamics ◽  
Output State ◽  
Microwave Cavities ◽  
Matter System ◽  
Two Level Systems ◽  
Extended Cavity ◽  
Photonic States

We propose a method to generate nonclassical states of light in multimode microwave cavities. Our approach considers two-photon processes that take place in a system composed of N extended cavities and an ultrastrongly coupled light–matter system. Under specific resonance conditions, our method generates, in a deterministic manner, product states of uncorrelated photon pairs, Bell states, and W states in different modes on the extended cavities. Furthermore, the numerical simulations show that the generation scheme exhibits a collective effect which decreases the generation time in the same proportion as the number of extended cavity increases. Moreover, the entanglement encoded in the photonic states can be transferred towards ancillary two-level systems to generate genuine multipartite entanglement. Finally, we discuss the feasibility of our proposal in circuit quantum electrodynamics. This proposal could be of interest in the context of quantum random number generator, due to the quadratic scaling of the output state.

Can quantum control modify thermodynamic behavior?

2014 ◽  
Vol 92 (2) ◽  
pp. 160-167 ◽  
Author(s):  
D. Gelbwaser-Klimovsky ◽  
N. Erez ◽  
R. Alicki ◽  
G. Kurizki
Keyword(s):  
Quantum Control ◽  
Correlation Energy ◽  
Thermal Bath ◽  
Equilibration Time ◽  
Memory Time ◽  
Two Level Systems ◽  
Entropy Reduction ◽  
Fast Control ◽  
Thermodynamical Behavior ◽  
Measurement Rate

We review the effects of frequent, impulsive quantum nondemolition measurements of the energy of two-level systems, alias qubits, in contact with a thermal bath. The resulting entropy and temperature of the system subject to measurements at intervals below the bath memory (Markovianity) time are completely determined by the measurement rate. Namely, they are unrelated to what is expected by standard thermodynamical behavior that holds for Markovian baths. These anomalies allow for very fast control of heating, cooling, and state-purification (entropy reduction) of qubits, much sooner than their thermal equilibration time. We further show that frequent measurements may enable the extraction of work in a closed cycle from the system−bath interaction (correlation) energy, a hitherto unexploited work resource. They allow for work even if no information is gathered or the bath is at zero temperature, provided the cycle is within the bath memory time.

scholarly journals Quantum Maps with Memory from Generalized Lindblad Equation

Entropy ◽  
2021 ◽  
Vol 23 (5) ◽  
pp. 544
Author(s):  
Vasily E. Tarasov
Keyword(s):  
Discrete Time ◽  
Power Law ◽  
Quantum Dynamics ◽  
Open Quantum Systems ◽  
Quantum Systems ◽  
Periodic Sequence ◽  
Lindblad Equation ◽  
Open Quantum ◽  
Systems With Memory ◽  
With Memory

In this paper, we proposed the exactly solvable model of non-Markovian dynamics of open quantum systems. This model describes open quantum systems with memory and periodic sequence of kicks by environment. To describe these systems, the Lindblad equation for quantum observable is generalized by taking into account power-law fading memory. Dynamics of open quantum systems with power-law memory are considered. The proposed generalized Lindblad equations describe non-Markovian quantum dynamics. The quantum dynamics with power-law memory are described by using integrations and differentiation of non-integer orders, as well as fractional calculus. An example of a quantum oscillator with linear friction and power-law memory is considered. In this paper, discrete-time quantum maps with memory, which are derived from generalized Lindblad equations without any approximations, are suggested. These maps exactly correspond to the generalized Lindblad equations, which are fractional differential equations with the Caputo derivatives of non-integer orders and periodic sequence of kicks that are represented by the Dirac delta-functions. The solution of these equations for coordinates and momenta are derived. The solutions of the generalized Lindblad equations for coordinate and momentum operators are obtained for open quantum systems with memory and kicks. Using these solutions, linear and nonlinear quantum discrete-time maps are derived.

Sign in / Sign up

Export Citation Format

Share Document