Statistical Mechanics
A quantum open system model of molecular battery charged by excitons (1903.12140v1)
Robert Alicki
2019-03-28
The analytically tractable model employing Quantum Markovian Master Equations, derived by weak coupling procedure and satisfying complete positivity, is proposed to describe a model of molecular battery charged by a non-equilibrium excitonic reservoir. The excitons are produced by non-equilibrium processes involving, e.g. light absorption and chemical reactions. Various relations concerning the efficiency of the involved processes of energy transfer and the stability of battery are discussed. The model can be treated as an initial step in applications of mathematically sound version of Quantum Theory of Open Systems to complex processes of energy transfer in biological system and man-made devices based on organic materials.
The Tangent Space to the Manifold of Critical Classical Hamiltonians Representable by Tensor Networks (1903.12137v1)
Yantao Wu
2019-03-28
We introduce a scheme to perform Monte Carlo Renormalization Group with the coupling constants of the system Hamiltonian encoded in a tensor network. With this scheme we compute the tangent space to the critical manifold at the nearest-neighbor critical coupling for three models: the two and three dimensional Ising models and the two dimensional three-state Potts model.
Noise-Induced Schooling of Fish (1903.12132v1)
Jitesh Jhawar, Richard G. Morris, U. R. Amith-Kumar, M. Danny Raj, Harikrishnan R., Vishwesha Guttal
2019-03-28
We report on the dynamics of collective alignment in groups of the cichlid fish, Etroplus suratensis. Focusing on small-to-intermediate sized groups (
), we demonstrate that schooling (highly polarised and coherent motion) is noise-induced, arising from the intrinsic stochasticity associated with finite numbers of interacting fish. The fewer the fish, the greater the (multiplicative) noise and therefore the likelihood of alignment. Such empirical evidence is rare, and tightly constrains the possible underlying interactions between fish: computer simulations indicate that E. suratensis align with each other one at a time, which is at odds with the canonical mechanism of collective alignment, local direction-averaging. More broadly, our results confirm that, rather than simply obscuring otherwise deterministic dynamics, noise is fundamental to the characterisation of emergent collective behaviours, suggesting a need to re-appraise aspects of both collective motion and behavioural inference.
Quantum valence bond ice theory for proton-driven quantum spin-dipole liquids (1903.03567v2)
Masahiko G. Yamada, Yasuhiro Tada
2019-03-08
We present a theory of a hybrid quantum liquid state,
(QSDL), in a hydrogen-bonded electron system, by combining a quantum proton ice and Anderson's resonating valence bond spin liquid, motivated by the recent experimental discovery of a proton-driven QSDL in
-H
(Cat-EDT-TTF)
(a.k.a. H-Cat). In our theory, an electron spin liquid and a proton dipole liquid are realized simultaneously in the ground state called
, while neither of them can be established independently of the other. Analytical and numerical calculations reveal that this state has a volume-law entanglement entropy between spins and dipoles, which is far beyond the (crude) Born-Oppenheimer approximation. We also examine the stability of QSDL with respect to perturbations and discuss implications for experiments in H-Cat and its deuterated analog D-Cat.
Microreversibility and driven Brownian motion with hydrodynamic long-time correlations (1903.12023v1)
Pierre Gaspard
2019-03-28
A nonequilibrium fluctuation theorem is established for a colloidal particle driven by an external force within the hydrodynamic theory of Brownian motion, describing hydrodynamic memory effects such as the t^(-3/2) power-law decay of the velocity autocorrelation function. The generalized Langevin equation is obtained for the general case of slip boundary conditions between the particle and the fluid. The Gaussian probability distributions for the particle to evolve in position-velocity space are deduced. It is proved that the joint probability distributions of forward and time-reversed paths have a ratio depending only on the work performed by the external force and the fluid temperature, in spite of the nonMarkovian character of the generalized Langevin process.
Don't forget to Follow and Resteem. @arxivsanity
Keeping everyone inform.