Physics – Condensed Matter – Mesoscale and Nanoscale Physics
Scientific paper
2001-06-08
in "Complexity from Microscopic to Macroscopic Scales: Coherence and Large Deviations", edited by Arne T. Skjeltorp and Tamas
Physics
Condensed Matter
Mesoscale and Nanoscale Physics
27 pages, 6 figures: submitted for "Complexity from Microscopic to Macroscopic Scales: Coherence and Large Deviations", NATO A
Scientific paper
We investigate the role of vacuum (zero-point) fluctuations in generating decoherence in a number of simple models. First we discuss a harmonic oscillator coupled to a semi-infinite elastic string and discuss the irreversible nature of such a bath. We investigate the fluctuations in energy of the oscillator and discuss the trace the oscillator leaves in the bath. Most of the work deals with two-level systems coupled to a bosonic bath (a transmission line). For two-level systems with a Hamiltonian that commutes with the total Hamiltonian (system plus coupling plus bath) the ground state is a pure state. The energy of the system is a constant of motion. For the general case, the energy of the two-level system fluctuates, and the ground state is only partially coherent. A particular realization of such a two level system consists of a mesoscopic ring with a quantum dot coupled capacitively to a transmission line. In the presence of an Aharonov-Bohm flux this system exhibits a persistent current. This current is a measure of the coherence of the ground state. As a function of the coupling strength the ground state undergoes a crossover from a state characterized by a time-averaged persistent current which is much larger than its time-averaged mean squared fluctuations to a state characterized by a persistent current with an average amplitude that is much smaller than its mean squared fluctuations.
No associations
LandOfFree
Irreversibility and Dephasing from Vacuum Fluctuations does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Irreversibility and Dephasing from Vacuum Fluctuations, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Irreversibility and Dephasing from Vacuum Fluctuations will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-419133