Latest Research Papers In Condensed Matter Physics | (Cond-Mat.Stat-Mech) 2019-04-10

arxivsanity (63)in #condensedmatter • 5 years ago

Latest Papers in Condensed Matter Physics

Statistical Mechanics

Leading order CFT analysis of multi-scalar theories in d>2 (1809.05071v2)

Alessandro Codello, Mahmoud Safari, Gian Paolo Vacca, Omar Zanusso

2018-09-13

We investigate multi-field multicritical scalar theories using CFT constraints on two- and three-point functions combined with the Schwinger-Dyson equation. This is done in general and without assuming any symmetry for the models, which we just define to admit a Landau-Ginzburg description that includes the most general critical interactions built from monomials of the form . For all such models we analyze to the leading order of the -expansion the anomalous dimensions of the fields and those of the composite quadratic operators. For models with even we extend the analysis to an infinite tower of composite operators of arbitrary order. The results are supplemented by the computation of some families of structure constants. We also find the equations which constrain the nontrivial critical theories at leading order and show that they coincide with the ones obtained with functional perturbative RG methods. This is done for the case as well as for all the even models. We ultimately specialize to symmetric models, which are related to the -state Potts universality class, and focus on three realizations appearing below the upper critical dimensions , and , which can thus be nontrivial CFTs in three dimensions.

Reputation-Driven Voting Dynamics (1902.09371v2)

D. Bhat, S. Redner

2019-02-22

We introduce the reputational voter model (RVM) to account for the time-varying abilities of individuals to influence their neighbors. To understand of the RVM, we first discuss the fitness voter model (FVM), in which each voter has a fixed and distinct fitness. In a voting event where voter is fitter than voter , only changes opinion. We show that the dynamics of the FVM and the voter model are identical. We next discuss the adaptive voter model (AVM), in which the influencing voter in a voting event increases its fitness by a fixed amount. The dynamics of the AVM is non-stationary and slowly crosses over to that of FVM because of the gradual broadening of the fitness distribution of the population. Finally, we treat the RVM, in which the voter is endowed with a reputational rank that ranges from 1 (highest rank) to (lowest), where is the population size. In a voting event in which voter outranks , only the opinion of changes. Concomitantly, the rank of increases, while that of does not change. The rank distribution remains uniform on the integers , leading to stationary dynamics. For equal number of voters in the two voting states with these two subpopulations having the same average rand, the time to reach consensus in the mean-field limit scales as . This long consensus time arises because the average rank of the minority population is typically higher than that of the majority. Thus whenever consensus is approached, this highly ranked minority tends to drive the population away from consensus.

Finite temperature effects on Majorana bound states in chiral -wave superconductors (1901.09933v2)

Henrik Schou Røising, Roni Ilan, Tobias Meng, Steven H. Simon, Felix Flicker

2019-01-28

We study Majorana fermions bound to vortex cores in a chiral -wave superconductor at temperatures non-negligible compared to the superconducting gap. Thermal occupation of Caroli de Gennes-Matricon states, below the full gap, causes the free energy difference between the two fermionic parity sectors to decay algebraically with increasing temperature. The power law acquires an additional factor of for each bound state thermally excited. The zero-temperature result is exponentially recovered well below the minigap (lowest-lying CdGM level). Our results suggest that temperatures larger than the minigap may not be disastrous for topological quantum computation. We discuss the prospect of precision measurements of pinning forces on vortices as a readout scheme for Majorana qubits.

Uncertainty relation in the presence of information measurement and feedback control (1904.04111v1)

Tan Van Vu, Yoshihiko Hasegawa

2019-04-08

Thermodynamic uncertainty relation, which provides a universal bound for relative fluctuation of arbitrary currents in nonequilibrium systems, has been developed for various systems. Here we study the uncertainty of dynamical observables for classical systems manipulated by repeated measurements and feedback control. In the presence of an external controller, the precision of observables is expected to be enhanced, but still be limited by the amount of information obtained from the measurement. We prove that the fluctuation of arbitrary observables that are antisymmetric under time reversal is constrained from below by the total entropy production and an informational quantity. This informational term is the sum of mutual entropy production and a Kullback--Leibler divergence which characterizes the irreversibility of measurement outcomes. The result holds for finite observation times and for both continuous- and discrete-time systems. We apply the derived relation to study the precision of a flashing ratchet, which is a type of Brownian ratchets.

The template-specific fidelity of DNA replication with high-order neighbor effects: a first-passage approach (1901.01495v2)

Qiu-Shi Li, Pei-Dong Zheng, Yao-Gen Shu, Zhong-Can Ou-Yang, Ming Li

2019-01-06

DNA replication fidelity is a critical issue in molecular biology. Biochemical experiments have provided key insights on the mechanism of fidelity control by DNAP in the past decades, whereas systematic theoretical studies on this issue began only recently. Because of the underlying difficulties of mathematical treatment, comprehensive surveys on the template-specific replication kinetics are still rare. Here we proposed a first-passage approach to address this problem, in particular the positional fidelity, for complicated processes with high-order neighbor effects. Under biologically-relevant conditions, we derived approximate analytical expressions of the positional fidelity which shows intuitively how some key kinetic pathways are coordinated to guarantee the high fidelity, as well as the high velocity, of the replication processes. It was also shown that the fidelity at any template position is dominantly determined by the nearest-neighbor template sequences, which is consistent with the idea that replication mutations are randomly distributed in the genome.

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