1,104 research outputs found
A scheme for tunable quantum phase gate and effective preparation of graph-state entanglement
A scheme is presented for realizing a quantum phase gate with three-level
atoms, solid-state qubits--often called artificial atoms, or ions that share a
quantum data bus such as a single mode field in cavity QED system or a
collective vibrational state of trapped ions. In this scheme, the conditional
phase shift is tunable and controllable via the total effective interaction
time. Furthermore, we show that the method can be used for effective
preparation of graph-state entanglement, which are important resources for
quantum computation, quantum error correction, studies of multiparticle
entanglement, fundamental tests of non-locality and decoherence.Comment: 7 pages, 5 figure
Demonstration of Einstein-Podolsky-Rosen Steering with Enhanced Subchannel Discrimination
Einstein-Podolsky-Rosen (EPR) steering describes a quantum nonlocal
phenomenon in which one party can nonlocally affect the other's state through
local measurements. It reveals an additional concept of quantum nonlocality,
which stands between quantum entanglement and Bell nonlocality. Recently, a
quantum information task named as subchannel discrimination (SD) provides a
necessary and sufficient characterization of EPR steering. The success
probability of SD using steerable states is higher than using any unsteerable
states, even when they are entangled. However, the detailed construction of
such subchannels and the experimental realization of the corresponding task are
still technologically challenging. In this work, we designed a feasible
collection of subchannels for a quantum channel and experimentally demonstrated
the corresponding SD task where the probabilities of correct discrimination are
clearly enhanced by exploiting steerable states. Our results provide a concrete
example to operationally demonstrate EPR steering and shine a new light on the
potential application of EPR steering.Comment: 16 pages, 8 figures, appendix include
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