Nondestructive probing of means, variances, and correlations of ultracoldatomicsystem densities via qubit impurities
Abstract
We show how impurity atoms can measure moments of ultracoldatomicgas densities, using the example of bosons in a onedimensional lattice. This builds on a body of work regarding the probing of systems by measuring the dephasing of an immersed qubit. We show that this dephasing is captured by a function resembling characteristic functions of probability theory, of which the derivatives at short times reveal moments of the system operator to which the qubit couples. For a qubit formed by an impurity atom, in a system of ultracold atoms, this operator can be the density of the system at the location of the impurity, and thus means, variances, and correlations of the atomic densities are accessible.
 Publication:

Physical Review A
 Pub Date:
 April 2016
 DOI:
 10.1103/PhysRevA.93.043612
 arXiv:
 arXiv:1602.02579
 Bibcode:
 2016PhRvA..93d3612E
 Keywords:

 Condensed Matter  Quantum Gases;
 Condensed Matter  Mesoscale and Nanoscale Physics;
 Physics  Atomic Physics;
 Quantum Physics
 EPrint:
 6 pages, 3 figures