From the Frenkel-Kontorova Model to Josephson Junction Arrays

Abstract

The Frenkel-Kontorova (FK) model is known to exhibit so-called Aubry's transition which is a jamming or frictional transition at zero temperature. Recently we found similar transition at zero and finite temperatures in a superconducting Josephson junction array (JJA) on a square lattice under external magnetic field. In the present paper we discuss how these problems are related.at North Dakota State University on July 6, 2015 http://ptps.oxfordjournals.org/ Downloaded from * ) The FK model with fixed volume (length) and that under fixed pressure (external force) behave completely differently. 11), 12) The former is relevant in the context of friction (jamming) and frustration is in some sense stronger than the latter. In the latter case the response of the system with respect to the increments of the external force exhibits devil's stair case singularities. Note also that the Hookian spring force, which arises due to the harmonic potential, does not endure the natural spacing l by itself.

Probing Axions with Event Horizon Telescope Polarimetric Measurements

“…It is most efficient to populate the highest possible L z state, i.e., m = l. For m < l, τ −1 SR is much smaller. Thus in the following discussion, we take m = l. The superradiance process keeps producing particles until the self-interaction among these bosons becomes important, which leads to non-linear region [34,35,[38][39][40]. In this region, one needs to take into account the whole potential in the effective Lagrangian…”

“…When the Compton wavelength of an axion is at the same order of a rotating black hole size, the axion is expected to develop a large density near the horizon, forming an axion cloud through the superradiance mechanism [25][26][27][28][29][30][31][32] (for a review see [33]). Such superradiance process can be tested by black hole spin measurements [34][35][36][37], gravitational wave signals from bosenova [34,35,[38][39][40][41][42] or electromagnetic emission from the axion cloud [43]. In this letter, we propose a novel way of detecting axion cloud around SMBH by using the polari-metric measurements of the EHT.…”

Transport and diffusion properties of interacting colloidal particles in two-dimensional microchannels with a periodic potential

“…At a certain threshold force the particles start to move, and for high forces the velocity slowly merges into the free velocity. Such a continuous depinning scenario seems to be a universal feature, since it can be found in many different systems ranging from classical colloids to quantum systems as mentioned in the Introduction [13,[19][20][21][22][23][24].…”

“…A continuous depinning at finite temperatures, as in the colloidal model systems [13,19], can also be found in quantum systems, such as the domain-wall motion in spin systems on nanofibers [20,21] or the dynamics in Josephson junction arrays [22][23][24].…”

Thermal phase transition in F(R) -charged AdS4 scalar theory

“…The question then arises as to what is expected as the final fate of an unstable black hole? A stable hairy black hole [5,6,28] or an explosion event called bosenova [30,31] are two possible candidates describing the final state of a superradiantly unstable system both in GR or alternatively in F (R) theories of gravity [8].…”