Search results for " Phase"

Weak-interaction and nuclear-structure aspects of nuclear double beta decay

1998

Abstract Weak-interaction and nuclear-structure aspects of double beta decay are reviewed. Starting from effective electroweak lagrangians, decay rates for the two-neutrino and neutrinoless modes of the nuclear double beta decay transitions are defined and second-order perturbative expressions for the nuclear decay amplitudes are given. Nuclear matrix elements of the relevant operators are presented, as extracted from data and from shell-model and QRPA calculations as well as from other theoretical approximations. The analysis is performed both for the two-neutrino and neutrinoless modes of the decay. The expressions for ground-state-to-ground-state and ground-state-to-excited-state transit…

Perturbative analysis of the 2νββ decays of 100Mo and 116Cd

2003

We have performed a theoretical analysis of the ground-state-to-ground-state transitions in 100Mo and 116Cd, based on the quasiparticle random-phase approximation and on a straightforward perturbative scheme. The results show that the single-state dominance found in the realistic calculations of the nuclear matrix elements, which is consistent with data, can be viewed as a result of the interference between few two-quasiparticle configurations.

Cross-phase modulational instability induced by Raman scattering in highly birefringent fiber

2013

We report experimental and theoretical studies of Raman-induced cross-phase modulational instabilities (XPMI) in a high-birefringence, normally dispersive optical fiber. Experimental results reveal that the Raman-Stokes wave, generated by a quasi-CW pump beam, interacts with the latter to create a novel type of XPMI sidebands. These sidebands are characterized by a narrow gain bandwidth. The sideband frequencies are well reproduced by a linear stability analysis as well as by full numerical solutions of the coupled generalized nonlinear Schrödinger equations.

Can entanglement be extracted from many body systems?

2007

Some thermodynamical properties of solids, such as heat capacity and magnetic susceptibility, have recently been shown to be linked to the amount of entanglement in a solid. Until now, however, it was not clear whether this entanglement can be used as a resource in quantum information theory. Here we show that this entanglement is physical, demonstrating the principles of its extraction from a typical spin chain by scattering two particles off the system. Moreover, we show how to simulate this process using present-day optical lattice technology. © 2007 World Scientific Publishing Company.

Phase-stable free-space optical lattices for trapped ions

2015

We demonstrate control of the absolute phase of an optical lattice with respect to a single trapped ion. The lattice is generated by off-resonant free-space laser beams, we actively stabilize its phase by measuring its ac-Stark shift on a trapped ion. The ion is localized within the standing wave to better than 2\% of its period. The locked lattice allows us to apply displacement operations via resonant optical forces with a controlled direction in phase space. Moreover, we observe the lattice-induced phase evolution of spin superposition states in order to analyze the relevant decoherence mechanisms. Finally, we employ lattice-induced phase shifts for inferring the variation of the ion pos…

OPCPA using beams shaped by diffractive optical elements

2011

Optical parametric chirped pulse amplification (OPCPA) is becoming a widely accepted technique for the generation of high energy ultrashort laser pulses. Flat-top spatial profile pump beams can improve the efficiency of OPCPA, however such beams can be energetically costly to generate and are difficult to implement for low pump energy systems. An elegant and efficient solution to the generation of flat-top spatial profiles is the use of a diffractive optical element (DOE), however these devices distort the geometric phase of the pulses, possibly making them unsuitable for phase coherent interactions such as OPCPA.

Unambiguous phase retrieval in fiber-based interferometers

2020

A scheme for fiber interferometers, exploiting frequency-multiplexing in orthogonal fiber polarization modes, enables unambiguous phase retrieval. This allows for arbitrary phase tuning, providing a precise tool for time-bin qubit manipulation.

2021

The fundamental nature of the neutrino is presently a subject of great interest. A way to access the absolute mass scale and the fundamental nature of the neutrino is to utilize the atomic nuclei through their rare decays, the neutrinoless double beta (0νββ) decay in particular. The experimentally measurable observable is the half-life of the decay, which can be factorized to consist of phase space factor, axial vector coupling constant, nuclear matrix element, and function containing physics beyond the standard model. Thus reliable description of nuclear matrix element is of crucial importance in order to extract information governed by the function containing physics beyond the standard m…

Constraining New Physics with the Fermilab Measurement ofCPViolation inB→ψKs

1999

Recently, the CDF Collaboration has reported a measurement of the CP asymmetry in the $B\ensuremath{\rightarrow}\ensuremath{\psi}{K}_{s}$ decay: ${a}_{\ensuremath{\psi}{K}_{s}}{\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.79}_{\ensuremath{-}0.44}^{+0.41}$. We analyze the constraints that follow from this measurement on the size and the phase of contributions from new physics to $B\ensuremath{-}\overline{B}$ mixing. Defining the relative phase between the full ${M}_{12}$ amplitude and the standard model contribution to be $2{\ensuremath{\theta}}_{d}$, we find a new bound: $\mathrm{sin}2{\ensuremath{\theta}}_{d}\ensuremath{\gtrsim}\ensuremath{-}0.6(\ensuremath{-}0.87)$ at $1\ensuremat…

Theories relating baryon asymmetry and dark matter

2014

The nature of dark matter and the origin of the baryon asymmetry are two of the deepest mysteries of modern particle physics. In the absence of hints regarding a possible solution to these mysteries, many approaches have been developed to tackle them simultaneously leading to very diverse and rich models. We give a short review where we describe the general features of some of these models and an overview on the general problem. We also propose a diagrammatic notation to label the different models.