9 research outputs found
Revealing nonclassicality beyond Gaussian states via a single marginal distribution
A standard method to obtain information on a quantum state is to measure
marginal distributions along many different axes in phase space, which forms a
basis of quantum state tomography. We theoretically propose and experimentally
demonstrate a general framework to manifest nonclassicality by observing a
single marginal distribution only, which provides a novel insight into
nonclassicality and a practical applicability to various quantum systems. Our
approach maps the 1-dim marginal distribution into a factorized 2-dim
distribution by multiplying the measured distribution or the vacuum-state
distribution along an orthogonal axis. The resulting fictitious Wigner function
becomes unphysical only for a nonclassical state, thus the negativity of the
corresponding density operator provides an evidence of nonclassicality.
Furthermore, the negativity measured this way yields a lower bound for
entanglement potential---a measure of entanglement generated using a
nonclassical state with a beam splitter setting that is a prototypical model to
produce continuous-variable (CV) entangled states. Our approach detects both
Gaussian and non-Gaussian nonclassical states in a reliable and efficient
manner. Remarkably, it works regardless of measurement axis for all
non-Gaussian states in finite-dimensional Fock space of any size, also
extending to infinite-dimensional states of experimental relevance for CV
quantum informatics. We experimentally illustrate the power of our criterion
for motional states of a trapped ion confirming their nonclassicality in a
measurement-axis independent manner. We also address an extension of our
approach combined with phase-shift operations, which leads to a stronger test
of nonclassicality, i.e. detection of genuine non-Gaussianity under a CV
measurement.Comment: 6 pages, 4 figures with Supplemental Informatio
Scalable and Programmable Phononic Network with Trapped Ions
Controllable bosonic systems can provide post-classical computational power
with sub-universal quantum computational capability. A network that consists of
a number of bosons evolving through beam-splitters and phase-shifters between
different modes, has been proposed and applied to demonstrate quantum
advantages. While the network has been implemented mostly in optical systems
with photons, recently alternative realizations have been explored, where major
limitations in photonic systems such as photon loss, and probabilistic
manipulation can be addressed. Phonons, the quantized excitations of
vibrational modes, of trapped ions can be a promising candidate to realize the
bosonic network. Here, we experimentally demonstrate a minimal-loss phononic
network that can be programmed and in which any phononic states are
deterministically prepared and detected. We realize the network with up to four
collective-vibrational modes, which can be straightforwardly extended to reveal
quantum advantage. We benchmark the performance of the network with an
exemplary algorithm of tomography for arbitrary multi-mode states with a fixed
total phonon number. We obtain reconstruction fidelities of 94.5 1.95 %
and 93.4 3.15 % for single-phonon and two-phonon states, respectively.
Our experiment demonstrates a clear and novel pathway to scale up a phononic
network for various quantum information processing beyond the limitations of
classical and other quantum systems
Staffing composition, offender profiles, and supervision in China’s community corrections
In 2003, the Chinese government began the use of community corrections to guide the reeducation and reform of offenders. Scholarly research within the field of community corrections has since begun, but the development of Chinese community corrections research is still in its infancy. There is little information about offenders and community corrections’ institutional organization and staffing. There is a dearth of comprehensive studies on the administrative process of community corrections, particularly pretrial investigation, transition of offenders, supervision, and a reward and punishment system. Thus, this study explored these flaws and omissions through research on offender profiles and the supervisors responsible for the development of Chinese community corrections