Ergodic and nonergodic many-body dynamics in strongly nonlinear lattices

Specialized techniques for solving the classical many-body problem are explored in the context of simple gases, more complicated gases, and gravitating systems. The chapter starts with a brief review of some important concepts from statistical mechanics and then introduces the classic Verlet method for obtaining the dynamics of many simple particles. The practical problems of setting the system temperature and measuring observables are discussed. The issues associated with simulating systems of complex objects form the next topic. One approach is to implement constrained dynamics, which can be done elegantly with iterative methods. Gravitational systems are introduced next with stress on techniques that are applicable to systems of different scales and to problems with long range forces. A description of the recursive Barnes-Hut algorithm and particle-mesh methods that speed up force calculations close out the chapter.

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Periodically refreshed baths to simulate open quantum many-body dynamics

Physical Review B ◽

10.1103/physrevb.104.045417 ◽

2021 ◽

Vol 104 (4) ◽

Author(s):

Archak Purkayastha ◽

Giacomo Guarnieri ◽

Steve Campbell ◽

Javier Prior ◽

John Goold

Keyword(s):

Many Body ◽

Open Quantum ◽

Body Dynamics

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Stacking angle dependent multiple excitonic resonances in bilayer tungsten diselenide

Nanophotonics ◽

10.1515/nanoph-2020-0034 ◽

2020 ◽

Vol 9 (12) ◽

pp. 3881-3887

Author(s):

Ankit Arora ◽

Pramoda K. Nayak ◽

Tejendra Dixit ◽

Kolla Lakshmi Ganapathi ◽

Ananth Krishnan ◽

...

Keyword(s):

Chemical Vapour ◽

Optoelectronic Devices ◽

Interlayer Coupling ◽

Higher Order ◽

Doping Effect ◽

Many Body ◽

Si Substrate ◽

Tungsten Diselenide ◽

Body Dynamics ◽

Insight Into

AbstractWe report on multiple excitonic resonances in bilayer tungsten diselenide (BL-WSe2) stacked at different angles and demonstrate the use of the stacking angle to control the occurrence of these excitations. BL-WSe2 with different stacking angles were fabricated by stacking chemical vapour deposited monolayers and analysed using photoluminescence measurements in the temperature range 300–100 K. At reduced temperatures, several excitonic features were observed and the occurrences of these exitonic resonances were found to be stacking angle dependent. Our results indicate that by controlling the stacking angle, it is possible to excite or quench higher order excitations to tune the excitonic flux in optoelectronic devices. We attribute the presence/absence of multiple higher order excitons to the strength of interlayer coupling and doping effect from SiO2/Si substrate. Understanding interlayer excitations will help in engineering excitonic devices and give an insight into the physics of many-body dynamics.

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ON STRONGLY NONLINEAR AUTOREGRESSIVE MODELS: IMPLICATIONS FOR THE THEORY OF TRANSIENT AND STATIONARY RESPONSES OF MANY-BODY SYSTEMS

Fluctuation and Noise Letters ◽

10.1142/s0219477513500223 ◽

2013 ◽

Vol 12 (04) ◽

pp. 1350022 ◽

Cited By ~ 1

Author(s):

T. D. FRANK ◽

S. MONGKOLSAKULVONG

Keyword(s):

Evolution Equations ◽

Mean Field Theory ◽

Mean Field ◽

Ar Model ◽

Many Body ◽

Response Dynamics ◽

Process Mean ◽

Stationary Response ◽

Strongly Nonlinear ◽

Many Body Systems

Two widely used concepts in physics and the life sciences are combined: mean field theory and time-discrete time series modeling. They are merged within the framework of strongly nonlinear stochastic processes, which are processes whose stochastic evolution equations depend self-consistently on process expectation values. Explicitly, a generalized autoregressive (AR) model is presented for an AR process that depends on its process mean value. Criteria for stationarity are derived. The transient dynamics in terms of the relaxation of the first moment and the stationary response to fluctuations in terms of the autocorrelation function are discussed. It is shown that due to the stochastic feedback via the process mean, transient and stationary responses may exhibit qualitatively different temporal patterns. That is, the model offers a time-discrete description of many-body systems that in certain parameter domains feature qualitatively different transient and stationary response dynamics.

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