[seminar] Seminar FO, Goold

[hbuljan at phy.hr]

Poštovani kolege,

sutra će nam predavanje naslovljeno "Qubit embedding in an
ultracold Fermi gas: Orthogonality Catastrophe Revisited"
održati John Goold iz Oxforda, UK.

Predavanje će se održati na Fizičkom odsjeku s početkom
u 14.15 sati u prostoriji F201.

Srdačan pozdrav
Hrvoje Buljan

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Vrijeme: 25.05.2011. (srijeda) 14.15
Mjesto: soba F201, Fizički odsjek, Bijenička c. 32

 Qubit embedding in an ultracold Fermi gas:
     Orthogonality Catastrophe Revisited

           John Goold
Clarendon Laboratory, University of Oxford, UK

We investigate the behavior of a single qubit coupled to a low-dimensional,
ultra-cold Fermi gas. The scattering between the system and the fermions
leads to the loss of any coherence in the initial state of the qubit and we
show that the exact dynamics of this process is strongly influenced by the
effect of the orthogonality catastrophe within the gas. We highlight the
relationship between the Loschmidt echo and the retarded Green's function -
typically used to formulate the dynamical theory of the catastrophe - and
demonstrate that the effect can be triggered and characterized via local
operations on the qubit. We demonstrate how the expected broadening of the
spectral function can be observed using Ramsey interferometry on the qubit.

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