arXiv subjects

Samyadeb Bhattacharya

Publications and source records attributed to Samyadeb Bhattacharya.

42 records · Page 3Linked to original sources

arXiv2014

Temperature dependent weak value of dwell time for a two state particle tunneling through a thermal magnetic barrier

Dwell time for a two state particle tunneling through a noisy thermal magnetic barrier has been calculated by studying the time evolution of the system. The effect of temperature has been included by averaging over the environmental magnetic modes. The time scale has been calculated in the framework of weak measurement. The dwell time initially increases with the rise of temperature and finally saturates. The increment of dwell time can be explained by the phenomena of quantum memory loss caused by efficient energy exchange with the environmental modes. The saturation region at higher temperature corresponds to the process of thermal hopping of the barrier.

quant-ph↗

arXiv2013

Laser trapping of ions and asymptotic minimization of Decoherence

Decoherence time has been calculated for an optical ion trap of Be atoms in a bistable potential model. Comparison has been made between decoherence time and Zeno time for double well potential as a special case. Zeno time is considered as a lower limit of decoherence time for sustainable quantum coherence. Equality of the respective timescales provides a certain transitional temperature, below which decoherence can be asymptotically minimized.

quant-ph↗

arXiv2013

Quatum Thermodynamics and the coherence in Ion channels

We showed that quantum mechanical superposition can sustain in the process of ion transfer in protein membrane for a substantial period, in spite of the presence of the interactions with environmental modes of molecular vibration. The spectral temperature, as defined in quantum thermodynamical framework plays a significant role in maintaining the coherence. The ratio of decoherence time and dwell time has been calculated, which can be directly related to the degree of coherence. The results shead new light to build quantum information system of entangled ionic states in the voltage gated biological channels.

quant-ph↗

arXiv2012

Hartman effect and dissipative quantum systems

The dwell time for dissipative quantum system is shown to increase with barrier width. It clearly precludes Hartman effect for dissipative systems. Here calculation has been done for inverted parabolic potential barrier.

quant-ph↗

arXiv2012

Weak measurement and Zeno time in a dissipative environment

A generalized expression for weak value of dwell time in dissipative systems has been constructed using the approach of Caldirola and Montaldi. An approximate measure of Zeno time has been found taking an asymmetric double well potential. Atomic tunneling between two surfaces is taken as a practical example. The formalism can be used for any solvable potential with exact or approximate energy eigenvalues.

quant-ph↗

arXiv2012

Weak value of Dwell time for Quantum Dissipative spin-1/2 System

The dwell time is calculated within the framework of time dependent weak measurement considering dissipative interaction between a spin half system and the environment. Caldirola and Montaldi's method of retarded Schroedinger equation is used to study the dissipative system. The result shows that inclusion of dissipative interaction prevents zero time tunneling.

quant-ph↗