Adiabatic elimination of Gaussian subsystems from quantum dynamics under continuous measurement
Abstract
An ever broader range of physical platforms provides the possibility to study and engineer quantum dynamics under continuous measurements. In many experimental arrangements the system of interest is monitored by means of an ancillary device, whose sole purpose is to transduce the signal from the system to the measurement apparatus. Here we present a method of adiabatic elimination when the transducer consists of an arbitrary number of bosonic modes with Gaussian dynamics while the measured object can be any quantum system. Crucially, our approach can cope with the highly relevant case of finite temperature of the transducer, which is not easily achieved with other methods. We show that this approach provides a significant improvement in the readout of superconducting qubits in circuit QED already for a few thermal excitations and makes it possible to adiabatically eliminate optomechanical transducers relevant for frequency conversion between microwave and optical fields.
- Publication:
-
Physical Review A
- Pub Date:
- July 2015
- DOI:
- 10.1103/PhysRevA.92.012124
- arXiv:
- arXiv:1503.07484
- Bibcode:
- 2015PhRvA..92a2124A
- Keywords:
-
- 03.65.Yz;
- 42.50.Lc;
- 42.50.Pq;
- 03.65.Ta;
- Decoherence;
- open systems;
- quantum statistical methods;
- Quantum fluctuations quantum noise and quantum jumps;
- Cavity quantum electrodynamics;
- micromasers;
- Foundations of quantum mechanics;
- measurement theory;
- Quantum Physics;
- Condensed Matter - Mesoscale and Nanoscale Physics
- E-Print:
- 13 pages + Appendix, 8 figures