arXiv subjects

YiJing Yan

Publications and source records attributed to YiJing Yan.

At least 37 records · Page 2Linked to original sources

arXiv2023

Kondo regime of the impurity spectral function and the current noise spectrum in the double impurity Anderson model

The dissipaton equations of motion (DEOM) method is one of the most popular methods for simulating quantum impurity systems. In this article, we use DOEM theory to deal with the Kondo problem of the double quantum dots (DQDs) impurity system. We focus on the impurity spectral function and the total noise spectral function, this two function will be used to describe the Kondo effect of this system. The influence of the interaction, the hooping and the difference of the chemical potential between the two dots on the Kondo effect of the system is studied. We find that the interaction between the two dots can influence the Kondo effect of the system a lot.

quant-ph↗

arXiv2023

Open quantum systems with nonlinear environmental backactions: Extended dissipaton theory versus core-system hierarchy construction

In this paper, we present a comprehensive account of quantum dissipation theories with the quadratic environment couplings. The theoretical development includes the Brownian solvation mode embedded hierarchical quantum master equations, a core-system hierarchy construction that verifies the extended dissipaton equation of motion (DEOM) formalism [R. X. Xu et al., J. Chem. Phys. 148, 114103 (2018)]. Developed are also the quadratic imaginary-time DEOM for equilibrium and the λ (t)-DEOM for nonequilibrium thermodynamics problems. Both the celebrated Jarzynski equality and Crooks relation are accurately reproduced, which in turn confirms the rigorousness of the extended DEOM theories. While the extended DEOM is more numerically efficient, the core-system hierarchy quantum master equation is favorable for ''visualizing'' the correlated solvation dynamics.

quant-ph↗

arXiv2022

Quantum mechanics of open systems: Dissipaton theories

This Perspective presents a comprehensive account of the dissipaton theories developed in our group since 2014, including the physical picture of dissipatons and the phase-space dissipaton algebra. The dissipaton-equation-of-motion-space (DEOM-space) formulations cover the Schrödinger picture, the Heisenberg picture, and further the imaginary-time DEOM. Recently developed are also the dissipaton theories for studying equilibrium and nonequilibrium thermodynamic mixing processes. The Jarzynski equality and Crooks relation are accurately reproduced numerically. It is anticipated that dissipaton theories would remain essential towards a maturation of quantum mechanics of open systems.

quant-ph↗

arXiv2022

Coherent excitation energy transfer in model photosynthetic reaction center: Effects of non-Markovian quantum environment

Excitation energy transfer (EET) and electron transfer (ET) are crucially involved in photosynthetic processes. In reality, the photosynthetic reaction center constitutes an open quantum system of EET and ET, which manifests an interplay of pigments, solar light and phonon baths. So far theoretical studies have been mainly based on master equation approaches in the Markovian condition. The non-Markovian environmental effect, which may play a crucial role, has not been sufficiently considered. In this work, we propose a mixed dynamic approach to investigate this open system. The influence of phonon bath is treated via the exact dissipaton equation of motion (DEOM) while that of photon bath is via the Lindblad master equation. Specifically, we explore the effect of non-Markovian quantum phonon bath on the coherent transfer dynamics and its manipulation on the current-voltage behavior. Distinguished from the results of completely Markovian Lindblad equation and those adopting classical environment description, the mixed DEOM-Lindblad simulations exhibit transfer coherence up to a few hundreds femtoseconds and the related environmental manipulation effect on current. These non-Markovian quantum coherent effects be extended tomore complex and realistic systems and be helpful to the design of organic photovoltaic devices.

quant-ph↗

arXiv2022

A statistical quasi-particles thermofield theory with Gaussian environments: System-bath entanglement theorem for nonequilibrium correlation functions

For open quantum systems, the Gaussian environmental dissipative effect can be represented by statistical quasi-particles, namely, dissipatons. We exploit this fact to establish the dissipaton thermofield theory. The resulting generalized Langevin dynamics of absorptive and emissive thermofield operators are effectively noise-resolved. The system-bath entanglement theorem is then readily followed between an important class of nonequilibrium steady-state correlation functions. All these relations are validated numerically. A simple corollary is the transport current expression, which exactly recovers the result obtained from the nonequilibrium Green's function formalism.

cond-mat.stat-mech↗

arXiv2022

Nonequilibrium work distributions in quantum impurity system-bath mixing processes

The fluctuation theorem, where the central quantity is the work distribution, is an important characterization of nonequilibrium thermodynamics. In this work, based on the dissipaton-equation-of-motion theory, we develop an exact method to evaluate the work distributions in quantum impurity system-bath mixing processes, in the presence of non-Markovian and strong couplings. Our results not only precisely reproduce the Jarzynski equality and Crooks relation, but also reveal rich information on large deviation. The numerical demonstrations are carried out with a spin-boson model system.

cond-mat.stat-mech↗

arXiv2022

Memory effect preserved time-local approach to noise spectrum of transport current

Within the second-order non-Markovian master equation description, we develop an efficient method for calculating the noise spectrum of transport current through interacting mesoscopic systems. By introducing proper current-related density operators, we propose a practical and very efficient time-local approach to compute the noise spectrum, including the asymmetric spectrum, which contains the full information of energy emission and absorption. We obtain an analytical formula of the current noise spectrum to characterize the nonequilibrium transport including electron-electron Coulomb interaction and the memory effect. We demonstrate the proposed method in transport through interacting-quantum-dots system, and find good agreement with the exact results under broad range of parameters.

cond-mat.mes-hall↗

arXiv2022

Correlated driving-and-dissipation equation for non-Condon spectroscopy with the Herzberg-Teller vibronic coupling

Correlated driving-and-dissipation equation (CODDE) is an optimized complete second-order quantum dissipation approach, which is originally concerned with the reduced system dynamics only. However, one can actually extract the hybridized bath dynamics from CODDE with the aid of dissipaton-equation-of-motion theory, a statistical quasi-particle quantum dissipation formalism. Treated as an one{dissipaton theory, CODDE is successfully extended to deal with the Herzberg-Teller vibronic couplings in dipole-field interactions. Demonstrations will be carried out on the non-Condon spectroscopies of a model dimer system.

physics.chem-ph↗

arXiv2022

Universal Prony fitting decomposition for optimized hierarchical quantum master equations

In this work, we propose the Prony fitting decomposition (PFD) as an accurate and efficient exponential series method, applicable to arbitrary interacting bath correlation functions. The resulting hierarchical equations of motion (HEOM) formalism is greatly optimized, especially in extremely low temperature regimes that would be inaccessible with other methods. For demonstration, we calibrate the present PFD against the celebrated Padé spectrum decomposition method, followed by converged HEOM evaluations on the single-impurity Anderson model system.

quant-ph↗

arXiv2022

Electron transfer under the Floquet modulation in donor-bridge-acceptor systems

Electron transfer (ET) processes are of broad interest in modern chemistry. With the advancements of experimental techniques, one may modulate the ET via such as the light-matter interactions. In this work, we study the ET under a Floquet modulation occurring in the donor-bridge-acceptor systems, with the rate kernels projected out from the exact disspaton equation of motion formalism. This together with the Floquet theorem enables us to investigate the interplay between the intrinsic non-Markovianity and the driving periodicity. The observed rate kernel exhibits a Herzberg-Teller-like mechanism induced by the bridge fluctuation subject to effective modulation.

physics.chem-ph↗

arXiv2021

Nonequilibrium system-bath entanglement theorem versus heat transport

In this work, we extend the recently established system-bath entanglement theorem (SBET) [J. Chem. Phys. 152, 034102 (2020)] to the nonequilibrium scenario, in which an arbitrary system couples to multiple Gaussian baths environments at different temperatures. While the existing SBET connects the entangled system-bath response functions to those of local systems, the extended theory is concerned with the nonequilibrium steady-state quantum transport current through molecular junctions. The new theory is established on the basis of the generalized Langevin equation, with a close relation to nonequilibrium thermodynamics in the quantum regime.

quant-ph↗

arXiv2021

Temperature-dependence of the subdivision potential in nanothermodynamics

Nanothermodynamics is the thermodynamics of small systems, which are signifcantly affected by their surrounding environments. In nanothermodynamics, Hill introduced the concept of subdivision potential, which charaterizes the non-extensiveness. In this work, we establish the quantum thermodynamic integration of the subdivision potential, which is identifed to be proportional to the difference between the thermal and von Neumann entropies, focusing on its temperature-dependence. As a result, it serves as a versatile tool to help analyze the origin of non-extensiveness in nanosystems.

cond-mat.stat-mech↗

arXiv2021

Quantum dissipation with nonlinear environment couplings: Stochastic fields dressed dissipaton equation of motion approach

Accurate and efficient simulation on quantum dissipation with nonlinear environment couplings remains nowadays a challenging task. In this work, we propose to incorporate the stochastic fields, which resolve just the nonlinear environment coupling terms, into the dissipaton-equation-of-motion (DEOM) construction. The stochastic fields are introduced via the Hubbard-Stratonovich transformation. After the transformation, the resulted stochastic-fields-dressed total Hamiltonian contains only linear environment coupling terms. On basis of that, a stochastic-fields-dressed DEOM (SFD-DEOM) can then be constructed. The resultant SFD-DEOM, together with the ensemble average over the stochastic fields, constitutes an exact and nonperturbative approach to quantum dissipation under nonlinear environment couplings. It is also of relatively high efficiency and stability due to the fact that only nonlinear environment coupling terms are dealt with stochastic fields while linear couplings are still treated as the usual DEOM. Numerical demonstrations are carried out on a two-state model system.

quant-ph↗

arXiv2021

Correlated vibration-solvent effects on the non-Condon exciton spectroscopy

Excitation energy transfer is crucially involved in a variety of systems. During the process, the non-Condon vibronic coupling and the surrounding solvent interaction may synergetically play important roles. In this work, we study the correlated vibration-solvent influences on the non-Condon exciton spectroscopy. Statistical analysis is elaborated for the overall vibration-plus-solvent environmental effects. Analytic solutions are derived for the linear absorption of monomer systems. General simulations are accurately carried out via the dissipaton-equation-of-motion approach. The resulted spectra in either the linear absorption or strong field regime clearly demonstrate the coherence enhancement due to the synergetic vibration-solvent correlation.

physics.chem-ph↗

arXiv2021

Marcus' electron transfer rate revisited via a Rice-Ramsperger-Kassel-Marcus analogue: A unified formalism for linear and nonlinear solvation scenarios

In the pioneering work by R. A. Marcus, the solvation effect on electron transfer (ET) processes was investigated, giving rise to the celebrated nonadiabatic ET rate formula. In this work, on the basis of the thermodynamic solvation potentials analysis, we reexamine Marcus' formula with respect to the Rice-Ramsperger-Kassel-Marcus (RRKM) theory. Interestingly, the obtained RRKM analogue, which recovers the original Marcus' rate that is in a linear solvation scenario, is also applicable to the nonlinear solvation scenarios, where the multiple curve{crossing of solvation potentials exists. Parallelly, we revisit the corresponding Fermi's golden rule results, with some critical comments against the RRKM analogue proposed in this work. For illustration, we consider the quadratic solvation scenarios, on the basis of physically well-supported descriptors.

physics.chem-ph↗

arXiv2020

Mechanism of current noise spectrum in a nonequilibirum Kondo dot system

We systematically study the nonequilibirum Kondo mechanisms of quantum noise spectrum based on the accurate dissipaton--equation--of--motion evaluations. By comparing the noise spectra between the equilibrium and nonequilibrium cases and between the non-Kondo and Kondo regimes, we identify the nonequilibrium Kondo features in the current noise spectrum, appearing in the region of $ω\in [-eV, eV]$. The Kondo characteristic at $ω=\pm eV=\pm (μ_{\rm L}-μ_{\rm R})$ display asymmetrical upturns and remarkable peaks in $S(ω)$ and $dS(ω)/dω$, respectively. These features are originated from the Rabi interference of the transport current dynamics, with the Kondo oscillation frequency of $|eV|$. The minor but very distinguishable inflections, crossing over $ω=-eV$ to $ω=+eV$, would be related to a sort of Kondo-Fano interference between two Kondo resonances channels.

cond-mat.mes-hall↗

arXiv2020

Theoretical formulations on thermodynamics of quantum impurity systems

In this work, we put forward the theoretical foundation toward thermodynamics of quantum impurity systems measurable in experiments. The theoretical developments involve the identifications on two types of thermodynamic entanglement free--energy spectral functions for impurity systems that can be either fermionic or bosonic or combined. Consider further the thermodynamic limit in which the hybrid environments satisfy the Gaussian--Wick's theorem. We then relate the thermodynamic spectral functions to the local quantum impurity systems spectral densities that are often experimentally measurable. Another type of inputs is the bare--bath coupling spectral densities, which could be accurately determined with various methods. Similar relation is also established for the nonentanglement component that exists only in anharmonic bosonic impurity systems. For illustration, we consider the simplest noninteracting systems, with focus on the strikingly different characteristics between the bosonic and fermionic scenarios.

quant-ph↗

arXiv2020

Equilibrium and transient thermodynamics: A unified dissipaton-space approach

This work presents a unified dissipaton-equation-of-motion (DEOM) theory and its evaluations on the Helmholtz free energy change due to the isotherm mixing of two isolated subsystems. One is a local impurity and another is a nonlocal Gaussian bath. DEOM constitutes a fundamental theory for such open quantum mixtures. To complete the theory, we construct also the imaginary-time DEOM formalism via an analytical continuation of dissipaton algebra, which would be limited to equilibrium thermodynamics. On the other hand, the real-time DEOM deals with both equilibrium structural and nonequilibrium dynamic properties. Its combination with the thermodynamic integral formalism would be a viable and accurate means to both equilibrium and transient thermodynamics. As illustrations, we report the numerical results on a spin--boson system, with elaborations on the underlying anharmonic features, the thermodynamic entropy versus the von Neumann entropy, and an indication of "solvent-cage" formation. Beside the required asymptotic equilibrium properties, the proposed transient thermodynamics also supports the basic spontaneity criterion.

cond-mat.stat-mech↗