1,987 research outputs found
Hybrid photonic entanglement: Realization, characterization and applications
We show that the quantum disentanglement eraser implemented on a two-photon
system from parametric down-conversion is a general method to create hybrid
photonic entanglement, namely the entanglement between different degrees of
freedom of the photon pair. To demonstrate this, we generate and characterize a
source with tunable degree of hybrid entanglement between two qubits, one
encoded in the transverse momentum and position of a photon, and the other in
the polarization of its partner. In addition, we show that a simple extension
of our setup enables the generation of two-photon qubit-qudit hybrid entangled
states. Finally, we discuss the advantages that this type of entanglement can
bring for an optical quantum network.Comment: Published versio
Geodesic Structure of the Schwarzschild Black Hole in Rainbow Gravity
In this paper we study the geodesic structure of the Schwarzschild black hole
in rainbow gravity analyzing the behavior of null and time-like geodesic. We
find that the structure of the geodesics essentially does not change when the
semi-classical effects are included. However, we can distinguish different
scenarios if we take into account the effects of rainbow gravity. Depending on
the type of rainbow functions under consideration, inertial and external
observers see very different situations in radial and non radial motion of a
test particles.Comment: Version to match the accepted one in MPL
A 300-800MHz Tunable Filter and Linearized LNA applied in a Low-Noise Harmonic-Rejection RF-Sampling Receiver
A multiband flexible RF-sampling receiver aimed at software-defined radio is presented. The wideband RF sampling function is enabled by a recently proposed discrete-time mixing downconverter. This work exploits a voltage-sensing LNA preceded by a tunable LC pre-filter with one external coil to demonstrate an RF-sampling receiver with low noise figure (NF) and high harmonic rejection (HR). The second-order LC filter provides voltage pre-gain and attenuates the source noise aliasing, and it also improves the HR ratio of the sampling downconverter. The LNA consists of a simple amplifier topology built from inverters and resistors to improve the third-order nonlinearity via an enhanced voltage mirror technique. The RF-sampling receiver employs 8 times oversampling covering 300 to 800 MHz in two RF sub-bands. The chip is realized in 65 nm CMOS and the measured gain across the band is between 22 and 28 dB, while achieving a NF between 0.8 to 4.3 dB. The IIP2 varies between +38 and +49 dBm and the IIP3 between -14 dBm and -9 dBm, and the third and fifth order HR ratios are more than 60 dB. The LNA and downconverter consumes 6 mW, and the clock generator takes 12 mW at 800 MHz RF.\ud
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