arXiv subjects

A. R. Bulsara

Publications and source records attributed to A. R. Bulsara.

3 recordsLinked to original sources

arXiv2005

Signatures of chaotic and non-chaotic-like behaviour in a non-linear quantum oscillator through photon detection

The driven non-linear duffing osillator is a very good, and standard, example of a quantum mechanical system from which classical-like orbits can be recovered from unravellings of the master equation. In order to generated such trajectories in the phase space of this oscillator in this paper we use a the quantum jumps unravelling together with a suitable application of the correspondence principle. We analyse the measured readout by considering the power spectra of photon counts produced by the quantum jumps. Here we show that localisation of the wave packet from the measurement of the oscillator by the photon detector produces a concomitant structure in the power spectra of the measured output. Furthermore, we demonstrate that this spectral analysis can be used to distinguish between different modes of the underlying dynamics of the oscillator.

quant-ph↗

arXiv2004

Persistent Entanglement in the Classical Limit

The apparent difficulty in recovering classical nonlinear dynamics and chaos from standard quantum mechanics has been the subject of a great deal of interest over the last twenty years. For open quantum systems - those coupled to a dissipative environment and/or a measurement device - it has been demonstrated that chaotic-like behaviour can be recovered in the appropriate classical limit. In this paper, we investigate the entanglement generated between two nonlinear oscillators, coupled to each other and to their environment. Entanglement - the inability to factorise coupled quantum systems into their constituent parts - is one of the defining features of quantum mechanics. Indeed, it underpins many of the recent developments in quantum technologies. Here we show that the entanglement characteristics of two `classical' states (chaotic and periodic solutions) differ significantly in the classical limit. In particular, we show that significant levels of entanglement are preserved only in the chaotic-like solutions.

quant-ph↗

arXiv2004

Giant Relaxation Oscillations in a Very Strongly Hysteretic SQUID ring-Tank Circuit System

In this paper we show that the radio frequency (rf) dynamical characteristics of a very strongly hysteretic SQUID ring, coupled to an rf tank circuit resonator, display relaxation oscillations. We demonstrate that the the overall form of these characteristics, together with the relaxation oscillations, can be modelled accurately by solving the quasi-classical non-linear equations of motion for the system. We suggest that in these very strongly hysteretic regimes SQUID ring-resonator systems may find application in novel logic and memory devices.

cond-mat.supr-con↗