Lower bounds on the size of general Schrödinger-cat states from experimental data

Authors:Florian Fröwis
Journal:Journal of Physics A: Mathematical and Theoretical 50, 114003 (2017)
DOI:http://dx.doi.org/10.1088/1751-8121/aa5a92
Abstract:Experimental progress with meso- and macroscopic quantum states (i.e. general Schrödinger-cat states) was recently accompanied by theoretical proposals on how to measure the merit of these efforts. So far, experiment and theory have been disconnected as theoretical analysis of actual experimental data was missing. Here, we consider a proposal for macroscopic quantum states that measures the extent of quantum coherence present in the system. For this, the quantum Fisher information is used. We calculate lower bounds from real experimental data. The results are expressed as an ‘effective size’, that is, relative to ‘classical’ reference states. We find remarkable numbers of up to 70 in photonic and atomic systems.
File:froewis2017a.pdf

BibTeX Source

@Article{1751-8121-50-11-114003,
  author =       "Florian Fröwis",
  title =        "Lower bounds on the size of general Schrödinger-cat states from experimental
                 data",
  journal =      "Journal of Physics A: Mathematical and Theoretical",
  volume =       "50",
  number =       "11",
  pages =        "114003",
  URL =          "http://stacks.iop.org/1751-8121/50/i=11/a=114003",
  year =         "2017",
  doi =          "10.1088/1751-8121/aa5a92",
  abstract =     "Experimental progress with meso- and macroscopic quantum states (i.e. general
                 Schrödinger-cat states) was recently accompanied by theoretical proposals on how
                 to measure the merit of these efforts. So far, experiment and theory have been
                 disconnected as theoretical analysis of actual experimental data was missing. Here,
                 we consider a proposal for macroscopic quantum states that measures the extent of
                 quantum coherence present in the system. For this, the quantum Fisher information
                 is used. We calculate lower bounds from real experimental data. The results are
                 expressed as an ‘effective size’, that is, relative to ‘classical’
                 reference states. We find remarkable numbers of up to 70 in photonic and atomic
                 systems.",
}