http://hdl.handle.net/2289/144 Search the Channel search http://dspace.rri.res.in:8080/jspui/simple-search http://hdl.handle.net/2289/5275 Title: Classical orbital magnetic moment in a dissipative stochastic system<br/><br/>Authors: Kumar, N.<br/><br/>Abstract: We present an analytical treatment of the dissipative-stochastic dynamics of a charged classical particle confined biharmonically in a plane with a uniform static magnetic field directed perpendicular to the plane. The stochastic dynamics gives a steady state in the long-time limit. We have examined the orbital magnetic effect of introducing a parametrized deviation (η-1) from the second fluctuation-dissipation relation that connects the driving noise and the frictional memory kernel in the standard Langevin dynamics. The main result obtained here is that the moving charged particle generates a finite orbital magnetic moment in the steady state, and that the moment shows a crossover from para- to diamagnetic sign as the parameter η is varied. It is zero for η=1 that makes the steady state correspond to equilibrium, as it should. The magnitude of the orbital magnetic moment turns out to be a nonmonotonic function of the applied magnetic field, tending to zero in the limit of an infinitely large as well as an infinitesimally small magnetic field. These results are discussed in the context of the classic Bohr-van Leeuwen theorem on the absence of classical orbital diamagnetism. Possible realization is also briefly discussed.<br/><br/>Description: Open Access Thu, 29 Dec 2011 22:58:59 GMT http://hdl.handle.net/2289/5257 Title: Additivity principle in high-dimensional deterministic systems<br/><br/>Authors: Saito, Keiji; Dhar, Abhishek<br/><br/>Abstract: The additivity principle (AP), conjectured by Bodineau and Derrida [Phys. Rev. Lett. 92, 180601 (2004)PRLTAO0031-900710.1103/PhysRevLett.92.180601], is discussed for the case of heat conduction in three-dimensional disordered harmonic lattices to consider the effects of deterministic dynamics, higher dimensionality, and different transport regimes, i.e., ballistic, diffusive, and anomalous transport. The cumulant generating function (CGF) for heat transfer is accurately calculated and compared with the one given by the AP. In the diffusive regime, we find a clear agreement with the conjecture even if the system is high dimensional. Surprisingly, even in the anomalous regime the CGF is also well fitted by the AP. Lower-dimensional systems are also studied and the importance of three dimensionality for the validity is stressed.<br/><br/>Description: Open Access. Thu, 15 Dec 2011 22:58:59 GMT http://hdl.handle.net/2289/5256 Title: Heat and work fluctuations for a harmonic oscillator<br/><br/>Authors: Sabhapandit, Sanjib<br/><br/>Abstract: The formalism of Kundu [J. Stat. Mech.1742-546810.1088/1742-5468/2011/03/P03007 P03007 (2011)], for computing the large deviations of heat flow in harmonic systems, is applied to the case of single Brownian particle in a harmonic trap and coupled to two heat baths at different temperatures. The large-τ form of the moment generating function <e-λQ>≈g(λ)exp[τμ(λ)], of the total heat flow Q from one of the baths to the particle in a given time interval τ, is studied and exact explicit expressions are obtained for both μ(λ) and g(λ). For a special case of the single particle problem that corresponds to the work done by an external stochastic force on a harmonic oscillator coupled to a thermal bath, the large-τ form of the moment generating function is analyzed to obtain the exact large deviation function as well as the complete asymptotic forms of the probability density function of the work.<br/><br/>Description: Open Access. Sun, 29 Jan 2012 22:58:59 GMT http://hdl.handle.net/2289/5254 Title: On the problem of nontransport of electrons in disordered systems (Anderson localization)<br/><br/>Authors: Athreya, K.B.; Subramanian, R.R.; Kumar, N.<br/><br/>Description: Open Access Fri, 29 Oct 1971 22:58:59 GMT