10 research outputs found
Sampling quantum phase space with squeezed states
We study the application of squeezed states in a quantum optical scheme for
direct sampling of the phase space by photon counting. We prove that the
detection setup with a squeezed coherent probe field is equivalent to the
probing of the squeezed signal field with a coherent state. An example of the
Schroedinger cat state measurement shows that the use of squeezed states allows
one to detect clearly the interference between distinct phase space components
despite losses through the unused output port of the setup.Comment: 6 pages LaTeX. Submitted to Optics Expres
Accuracy of Sampling Quantum Phase Space in Photon Counting Experiment
We study the accuracy of determining the phase space quasidistribution of a
single quantized light mode by a photon counting experiment. We derive an exact
analytical formula for the error of the experimental outcome. This result
provides an estimation for the experimental parameters, such as the number of
events, required to determine the quasidistribution with assumed precision. Our
analysis also shows that it is in general not possible to compensate the
imperfectness of the photodetector in a numerical processing of the
experimental data. The discussion is illustrated with Monte Carlo simulations
of the photon counting experiment for the coherent state, the one photon Fock
state, and the Schroedinger cat state.Comment: 11 pages REVTeX, 5 figures, uses multicol, epsfig, and pstricks.
Submitted to Special Issue of Journal of Modern Optics on Quantum State
Preparation and Measuremen
Operational Time of Arrival in Quantum Phase Space
An operational time of arrival is introduced using a realistic position and
momentum measurement scheme. The phase space measurement involves the dynamics
of a quantum particle probed by a measuring device. For such a measurement an
operational positive operator valued measure in phase space is introduced and
investigated. In such an operational formalism a quantum mechanical time
operator is constructed and analyzed. A phase space time and energy uncertainty
relation is derived.Comment: 23 pages, 5 figures, to appear in Phys. Rev.
Nonlocality of the Einstein-Podolsky-Rosen state in the phase space
We discuss violation of Bell inequalities by the regularized
Einstein-Podolsky-Rosen (EPR) state, which can be produced in a quantum optical
parametric down-conversion process. We propose an experimental photodetection
scheme to probe nonlocal quantum correlations exhibited by this state.
Furthermore, we show that the correlation functions measured in two versions of
the experiment are given directly by the Wigner function and the Q function of
the EPR state. Thus, the measurement of these two quasidistribution functions
yields a novel scheme for testing quantum nonlocality.Comment: 10 pages LaTeX, contribution to proceedings of 6th central-european
workshop on quantum optic
Fractional Talbot effect in phase space: A compact summation formula
A phase space description of the fractional Talbot effect, occurring in a
one-dimensional Fresnel diffraction from a periodic grating, is presented.
Using the phase space formalism a compact summation formula for the Wigner
function at rational multiples of the Talbot distance is derived. The summation
formula shows that the fractional Talbot image in the phase space is generated
by a finite sum of spatially displaced Wigner functions of the source field.Comment: 4 pages, LaTeX. Submitted to Optics Expres
Dedication
Theoretical investigations of separability and entanglement of bipartite quantum systems b