Portal de Periódicos da CAPES

Orthogonality catastrophe as a consequence of qubit embedding in an ultracold Fermi gas

2011; American Physical Society; Volume: 84; Issue: 6 Linguagem: Inglês

10.1103/physreva.84.063632

1538-4446

John Goold, Thomás Fogarty, N. Lo Gullo, Mauro Paternostro, Thomas Busch,

Quantum, superfluid, helium dynamics

We investigate the behaviour 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.