Access
To read this story in full you will need to login or make a payment (see right).
Letter
Nature 452, 724-727 (10 April 2008) | doi:10.1038/nature06873; Received 18 October 2007; Accepted 26 February 2008
nature jobs
Postdoctoral Fellow - Two Posts
- Wellcome Trust Sanger Institute
- Cambridge CB10 1SA United Kingdom
Senior Scientist and Leader - Pathogen and Host Diversity Assessment and Gene Discovery
- International Livestock Research Institute
- Nairobi Kenya
Thermodynamic control by frequent quantum measurements
Noam Erez1, Goren Gordon1, Mathias Nest2 & Gershon Kurizki1
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
- Theoretische Chemie, Universitaet Potsdam, Potsdam 14476, Germany
Correspondence to: Gershon Kurizki1 Correspondence and requests for materials should be addressed to G.K. (Email: gershon.kurizki@weizmann.ac.il).
Abstract
Heat flow between a large thermal 'bath' and a smaller system brings them progressively closer to thermal equilibrium while increasing their entropy1. Fluctuations involving a small fraction of a statistical ensemble of systems interacting with the bath result in deviations from this trend. In this respect, quantum and classical thermodynamics are in agreement1, 2, 3, 4, 5. Here we predict a different trend in a purely quantum mechanical setting: disturbances of thermal equilibrium between two-level systems (TLSs) and a bath6, caused by frequent, brief quantum non-demolition7, 8, 9, 10 measurements of the TLS energy states. By making the measurements increasingly frequent, we encounter first the anti-Zeno regime and then the Zeno regime (namely where the TLSs' relaxation respectively speeds up and slows down11, 12, 13, 14, 15). The corresponding entropy and temperature of both the system and the bath are then found to either decrease or increase depending only on the rate of observation, contrary to the standard thermodynamical rules that hold for memory-less (Markov) baths2, 5. From a practical viewpoint, these anomalies may offer the possibility of very fast control of heat and entropy in quantum systems, allowing cooling and state purification over an interval much shorter than the time needed for thermal equilibration or for a feedback control loop.
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
- Theoretische Chemie, Universitaet Potsdam, Potsdam 14476, Germany
Correspondence to: Gershon Kurizki1 Correspondence and requests for materials should be addressed to G.K. (Email: gershon.kurizki@weizmann.ac.il).
To read this story in full you will need to login or make a payment (see right).
MORE ARTICLES LIKE THIS
These links to content published by NPG are automatically generated.
RESEARCH
Resolving photon number states in a superconducting circuitNature Letters to Editor (01 Feb 2007)
Strong dispersive coupling of a high-finesse cavity to a micromechanical membraneNature Letters to Editor (06 Mar 2008)
Entanglement and the foundations of statistical mechanicsNature Physics Article (01 Nov 2006)
Entanglement and the foundations of statistical mechanicsNature Physics Article
Acceleration of quantum decay processes by frequent observationsNature Letters to Editor (01 Jun 2000)
See all 8 matches for Research