Multiple symbol differential detection

A differential detection technique for multiple phase shift keying (MPSK) signals is provided which uses a multiple symbol observation interval on the basis of which a joint decision is made regarding the phase of the received symbols. In accordance with the invention, a first difference phase is created between first and second received symbols. Next, the first difference phase is correlated with the possible values thereof to provide a first plurality of intermediate output signals. A second difference phase is next created between second and third received symbols. The second difference phase is correlated with plural possible values thereof to provide a second plurality of intermediate output signals. Next, a third difference phase is created between the first and third symbols. The third difference phase is correlated with plural possible values thereof to provide a third plurality of intermediate output signals. Each of the first plurality of intermediate outputs are combined with each of the second plurality of intermediate outputs and each of the third plurality of intermediate outputs to provide a plurality of possible output values. Finally, a joint decision is made by choosing from the plurality of possible output values the value which represents the best combined correlation of the first, second and third difference values with the possible values thereof

Analytical investigation for multiplicity difference correlators under QGP phase transition

It is suggested that the study of multiplicity difference correlators between two well-separated bins in high-energy heavy-ion collisions can be used as a means to detect evidence of a quark-hadron phase transition. Analytical expressions for the scaled factorial moments of multiplicity difference distribution are obtained in a kinetical region ${\bar s}\le 0.3$ within Ginzburg-Landau description. It is shown that the scaling behaviors between the moments are still valid, though the behaviors of the moments with respect to the bin size are completely different from the so-called intermittency patterns. A universal exponent $\gamma$ is given to describe the dynamical fluctuations in the phase transition.Comment: 5 pages, RevTeX, three figures in EPS forma

Role of the relative phase in the merging of two independent Bose-Einstein condensates

We study the merging of two independent Bose-Einstein condensates with arbitrary initial phase difference, in the framework of a one-dimensional time-dependent Gross-Pitaevskii model. The role of the initial phase difference in the process is discussed, and various types of phase-sensitive excitations are identified.Comment: 19 Pages, 7 figure

Spontaneous photon emission stimulated by two Bose condensates

We show that the phase difference of two overlapping ground state Bose-Einstein condensates can effect the optical spontaneous emission rate of excited atoms. Depending on the phase difference the atom stimulated spontaneous emission rate can vary between zero and the rate corresponding to all the ground state atoms in a single condensate. Besides giving control over spontaneous emission this provides an optical method for detecting the condensate phase difference. It differs from previous methods in that no light fields are applied. Instead the light is spontaneously emitted when excited atoms make a transition into either condensate.Comment: 14 pages, 2 postscript figures, Revtex. Corrections and significant additions in revisio

Second Order Topological Superconductivity in π\pi-Junction Rashba Layers

We consider a Josephson junction bilayer consisting of two tunnel-coupled two-dimensional electron gas layers with Rashba spin-orbit interaction, proximitized by a top and bottom $s$-wave superconductor with phase difference $\phi$ close to $\pi$. We show that, in the presence of a finite weak in-plane Zeeman field, the bilayer can be driven into a second order topological superconducting phase, hosting two Majorana corner states (MCSs). If $\phi=\pi$, in a rectangular geometry, these zero-energy bound states are located at two opposite corners determined by the direction of the Zeeman field. If the phase difference $\phi$ deviates from $\pi$ by a critical value, one of the two MCSs gets relocated to an adjacent corner. As the phase difference $\phi$ increases further, the system becomes trivially gapped. The obtained MCSs are robust against static and magnetic disorder. We propose two setups that could realize such a model: one is based on controlling $\phi$ by magnetic flux, the other involves an additional layer of randomly-oriented magnetic impurities responsible for the phase shift of $\pi$ in the proximity-induced superconducting pairing

Optical stabilization of voltage fluctuations in half-Josephson lasers

A recently proposed device, dubbed half-Josephson laser, provides a phase-lock between the optical phase and the superconducting phase difference between the leads of the device. In this paper we propose to utilize this phase-lock for stabilization of voltage fluctuations, by two optical feedback schemes. The first scheme involves a single half-Josephson laser and allows to significantly decrease the diffusion coefficient of the superconducting phase difference. The second scheme involves a stable optical source and a fluctuating half-Josephson laser and permits quenching of the diffusion of the relative phase of the lasers. This opens up perspectives of the optical control of the superconducting phase and voltage fluctuations.Comment: 6 pages, 3 figure

Anomalous Josephson current through a ferromagnetic trilayer junction

We studied the anomalous Josephson current appearing at zero phase difference in junctions coupled with a ferromagnetic trilayer which has noncoplanar magnetizations. A $\pi/2$ junction with an equilibrium phase difference $\pi/2$ is obtained under suitable conditions. The equilibrium phase difference and the amplitude of the supercurrent are all tunable by the structure parameters. In addition to calculating the anomalous current using the Bogoliubov-de Gennes equation, we also developed a clear physical picture explaining the anomalous Josephson effect in the structure. We show that the triplet proximity correlation and the phase shift in the anomalous current-phase relation all stem from the spin precession in the first and third ferromagnet layers.Comment: 7 pages, 8 figures, accepted to PR