36,252 research outputs found
Antimagnetic Rotation Band in Nuclei: A Microscopic Description
Covariant density functional theory and the tilted axis cranking method are
used to investigate antimagnetic rotation (AMR) in nuclei for the first time in
a fully self-consistent and microscopic way. The experimental spectrum as well
as the B(E2) values of the recently observed AMR band in 105Cd are reproduced
very well. This gives a further strong hint that AMR is realized in specific
bands in nuclei.Comment: 10 pages, 4 figure
A Simplified Scheme of Estimation and Cancellation of Companding Noise for Companded Multicarrier Transmission Systems
Nonlinear companding transform is an efficient method to reduce the high peak-to-average power ratio (PAPR) of multicarrier transmission systems. However, the introduced companding noise greatly degrades the bit-error-rate (BER) performance of the companded multicarrier systems. In this paper, a simplified but effective scheme of estimation and cancellation of companding noise for the companded multicarrier transmission system is proposed. By expressing the companded signals as the summation of original signals added with a companding noise component, and subtracting this estimated companding noise from the received signals, the BER performance of the overall system can be significantly improved. Simulation results well confirm the great advantages of the proposed scheme over other conventional decompanding or no decompanding schemes under various situations
Generalized reflection symmetry and leptonic CP violation
We propose a generalized reflection symmetry to constrain the
lepton flavor mixing parameters. We obtain a new correlation between the
atmospheric mixing angle and the "Dirac" CP violation phase
. Only in a specific limit our proposed CP transformation
reduces to standard reflection, for which and
are both maximal. The "Majorana" phases are predicted to lie at
their CP-conserving values with important implications for the neutrinoless
double beta decay rates. We also study the phenomenological implications of our
scheme for present and future neutrino oscillation experiments including T2K,
NOA and DUNE.Comment: 14 pages, 9 figures, latex, Final version to appear in Physics
Letters
SU(2)-in-SU(1,1) Nested Interferometer for Highly Sensitive, Loss-Tolerant Quantum Metrology
We present experimental and theoretical results on a new interferometer
topology that nests a SU(2) interferometer, e.g., a Mach-Zehnder or Michelson
interferometer, inside a SU(1,1) interferometer, i.e., a Mach-Zehnder
interferometer with parametric amplifiers in place of beam splitters. This
SU(2)-in-SU(1,1) nested interferometer (SISNI) simultaneously achieves high
signal-to-noise ratio (SNR), sensitivity beyond the standard quantum limit
(SQL) and tolerance to photon losses external to the interferometer, e.g., in
detectors. We implement a SISNI using parametric amplification by four-wave
mixing (FWM) in Rb vapor and a laser-fed Mach-Zehnder SU(2) interferometer. We
observe path-length sensitivity with SNR 2.2 dB beyond the SQL at power levels
(and thus SNR) 2 orders of magnitude beyond those of previous loss-tolerant
interferometers. We find experimentally the optimal FWM gains and find
agreement with a minimal quantum noise model for the FWM process. The results
suggest ways to boost the in-practice sensitivity of high-power
interferometers, e.g., gravitational wave interferometers, and may enable
high-sensitivity, quantum-enhanced interferometry at wavelengths for which
efficient detectors are not available.Comment: 6 pages + 4 of supplemental material, 5 figure
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