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Pre-hospital triage supported by electrocardiogram assessment and telemedicine was used to shorten time to reperfusion in subjects with acute myocardial infarction (AMI). Timely treatment of AMI presupposes huge geographical areas covered by one primary angioplasty network, one emergency medical service (EMS), and that pre-hospital electrocardiograms are interpreted by a physician, preferably a cardiologist.

Increasing the information-carrying capacity of a single photon may be achieved by utilizing multiple degrees of freedom. We describe here an approach that utilizes two degrees of freedom to encode three qubits per photon: one in polarization and two in the spatial-parity symmetry of the transverse field. In this conception, a polarization-sensitive spatial light modulator corresponds to a three-qubit controlled-unitary gate with one control qubit (polarization) and two target (spatial-parity-symmetry) qubits. We describe the construction of controlled-NOT (CNOT), n√CNOT, controlled-PHASE, and Fredkin gates, and the preparation of one-photon, three-qubit Greenberger-Horne-Zeilinger (GHZ) and W states. This approach enables simple optical implementations of few-qubit tasks in quantum information processing. [ABSTRACT FROM AUTHOR]

We describe an optical implementation of a CNOT gate in which the control qubit is the polarization of a single photon and the target qubit is the spatial parity of the same photon. The gate is implemented with a polarizationsensitive spatial light modulator. We characterize the operation of the gate using quantum process tomography and the spatial parity is analyzed with a modified Mach-Zehnder interferometer. We also demonstrate the CNOT-gate operation with arbitrary rotation of the target qubit and discuss the possibility of implementing multi-qubit CNOT gates using the same approach.

In the propagation of optical pulses through dispersive media, the frequency degree of freedom acts as an effective decohering environment on the polarization state of the pulse. Here we discuss the application of open-loop dynamical-decoupling techniques for suppressing such a polarization decoherence in one-way communication channels. We describe in detail the experimental proof of principle of the "bang-bang" protection technique recently applied to flying qubits in Damodarakurup et al. [Phys. Rev. Lett. 103, 040502 (2009)]. Bang-bang operations are implemented through appropriately oriented wave plates and dynamical decoupling is shown to be potentially useful to contrast a generic decoherence acting on polarization qubits propagating in dispersive media like optical fibers. [ABSTRACT FROM AUTHOR]

We propose a scheme for the generation of a robust stationary squeezed state of a mechanical resonator in a quadratically coupled optomechanical system, driven by a pulsed laser. The intracavity photon number presents periodic intense peaks suddenly stiffening the effective harmonic potential felt by the mechanical resonator. These "optical spring kicks" tend to squeeze the resonator position, and due to the interplay with fluctuation-dissipation processes one can generate a stationary state with more than 10 dB of squeezing in a realistic scenario, even starting from moderately "precooled" initial thermal states. [ABSTRACT FROM AUTHOR]

We demonstrate the analog of electromagnetically induced transparency in a room temperature cavity optomechanics setup formed by a thin semitransparent membrane within a Fabry-Pérot cavity. Due to destructive interference, a weak probe field is completely reflected by the cavity when the pump beam is resonant with the motional red sideband of the cavity. Under this condition we infer a significant slowing down of light of hundreds of microseconds, which is easily tuned by shifting the membrane along the cavity axis. We also observe the associated phenomenon of electromagnetically induced amplification which occurs due to constructive interference when the pump is resonant with the blue sideband. [ABSTRACT FROM AUTHOR]