Counting quantum fluctuations of particle density
2012 (English)In: Annalen der Physik, ISSN 0003-3804, E-ISSN 1521-3889, Vol. 524, no 3-4, 163-174 p.Article in journal (Refereed) Published
Methods of charge projectors using special gauge transformations for tagging particles are presented. Such engineering of a many-body wave function allows extracting information regarding properties of a physical system beyond average values. The method is first used to establish under which circumstances the properties of particle currents can be understood as discrete transfers of particles from one region to another. Next, the method is extended to show that in a tunnel junction coupled to a two-level system, the transmission of electrical noise causes decoherence and thereby a projective measurement of the two-level system as encoded by the amount of tunnelled charge. Finally the method is extended to deal with the exceptional circumstance where a measurement on a system with a large number of particles gives macroscopically distinguishable outcomes that are unpredictable, the observed interference pattern of interfering BEC's.
Place, publisher, year, edition, pages
Weinheim, Germany: Wiley-VCH Verlagsgesellschaft, 2012. Vol. 524, no 3-4, 163-174 p.
Quantum measurement, charge projectors, counting statistics, BEC interference
IdentifiersURN: urn:nbn:se:umu:diva-54313DOI: 10.1002/andp.201100277ISI: 000301772400017OAI: oai:DiVA.org:umu-54313DiVA: diva2:523453