The last decade has witnessed continuously growing interest in the investigation of spin degrees of freedom in various systems in solid-state physics, atomic physics, optics, and acoustics. The dynamics of spin (or quasi-spin) becomes especially intriguing when it interacts with other degrees of freedom. A well-known example of such interaction is the coupling between spinor and translational degrees of freedom, known as spin-orbit coupling. One of the most spectacular manifestations of the spin-orbit coupling is the appearance of in-gap topological edge states at the boundaries or interfaces between periodic structures. Such topological edge states are particularly robust because they are immune to weak disorder and to absence of backscattering by surface defects. Novel prospects for the exploration of the physics of topological edge states and insulators open in systems of neutral atoms placed in periodic potentials, where diverse gauge potentials can be artificially created. Here, we suggest a new platform, where topological edge states emerge due to the interplay between spin-orbit coupling and a Zeeman lattice, characterized by opposite signs for the spinor components. We illustrate strong effect of different components of spin-orbit coupling on the emergence of the topological states. We also obtain nonlinear edge states and study their instabilities in the presence of interatomic interaction in spin-orbit coupled Bose-Einstein condensates.Discrete and continuous lattices exhibit degeneracies in the eigenmode spectrum when the corresponding Hamiltonian is characterized by suitable spatial symmetries and time-reversal invariance [1]. Graphene, as the paradigm of a honeycomb lattice [2], is one of the best-known examples of structures where energy bands touch at Dirac points. If the underlying symmetries are broken, a gap may open at the Dirac points thus leading to a transition to either a conventional or a topological insulator phase, depending on which symmetry is broken [1]. When such a lattice is located in contact with a material having distinct topological properties, topological states with energies falling into the gap and localized at the edge between two materials may appear. An outstanding perturbation that leads to the appearance of topological edge states is spin-orbit coupling (SOC), which in electronic systems gives rise to the quantum spin Hall effect [3,4].Interest in topological edge states is constantly growing [4,5] and to date the concept of topological insulation has been extended to several areas of physics, where SOC can be emulated by coupling the translational and the internal spinor degrees of freedom, the latter often referred as pseudo-spin. Topological insulators have been realized in acoustic [6] and mechanical systems [7], as well as in optical and optoelectronic systems [8], including gyromagnetic photonic crystals [9][10][11], semiconductor quantum wells [12], arrays of coupled resonators [13,14], metamaterial superlattices [15], helical waveguide arrays [16][17][18], system...

We address propagation of light in nonlinear twisted multi-core fibers with alternating amplifying and absorbing cores that are arranged into the PTsymmetric structure. In this structure, the coupling strength between neighboring cores and global energy transport can be controlled not only by the nonlinearity strength, but also by gain and losses and by the fiber twisting rate. The threshold level of gain/losses, at which PT -symmetry breaking occurs, is a non-monotonic function of the fiber twisting rate and it can be reduced nearly to zero or, instead, notably increased just by changing this rate. Nonlinearity usually leads to the monotonic reduction of the symmetry breaking threshold in such fibers.OCIS codes : (190.5940) (070.7345 The concept of parity-time ( ) PT symmetry that was initially introduced in quantum mechanics [1], has already penetrated into many other areas of science (see [2,3] for recent reviews). Various optical realizations of the PT -symmetric systems, such as couplers, multi-core fibers, shallow photonic lattices, and photonic crystals with inhomogeneous refractive index landscapes obeying the PT symmetry condition ( ) ( ) n n * = -r r , where ( ) n r is the complex refractive index, were suggested. Despite the presence of gain and losses in such systems, the internal currents from amplifying to absorbing domains make it possible for the propagation of the beam without net amplification or attenuation. The most representative property of the PT -symmetric system is the existence of the threshold level of gain/losses, above which the spectrum of the system becomes complex and the propagation of the modes is always accompanied by their amplification or attenuation [4]. The breakup of the PT symmetry was observed experimentally [5,6]. PT -symmetric structures that remain invariable in the direction of light propagation have been used for demonstration of the switching, localization, and nonreciprocal soliton scattering [7][8][9][10][11][12][13]. At the same time, longitudinal variation of the parameters of a PT -symmetric system substantially enrich the spectrum of the available phenomena. Such dynamic structures were used for illustration of the pseudo-PT symmetry [14][15][16] The PT symmetry-breaking threshold depends on several factors, most notably on the size of the system. Usually, this threshold decreases with the increase in the number of elements (for example, waveguides) in the system [22]. However, interesting exceptions are encountered in the discrete circular waveguide arrays, where the threshold changes in a step-like fashion with the increase in the number of waveguides [23,24]. Similar size effects were encountered in complex photonic crystals [25,26]. At the same time, longitudinal modulations of the parameters of the PT -symmetric systems also notably affect the symmetry-breaking threshold [15]. An interesting approach to control the PT -symmetry breaking threshold was introduced in [27], where it was shown that the geometric twist leads to the nonmonotonic variation o...

A: Very large Liquid Xenon (LXe) Time Projection Chambers (TPC) are employed to search for Dark Matter (DM). The DM particles are supposed to interact with the whole nucleus, compared to background of γ-rays, which interact with the electrons. Therefore, DM signals are caused by Nuclear Recoil (NR) instead of the Electron Recoils (ER). In ER and NR events differ in pulse shape since the ratios of light from direct scintillation and recombination are different. To discriminate against residual ER events would be possible if one can distinguish the differences in decay times. This method can be successfully applied in Liquid Argon TPCs. In LXe, however, it is generally assumed that these differences are too small to be distinguished at low energies.The easiest algorithm of Pulse Shape Discrimination (PSD) distinguishes the event type based on the number of photons emitted much later than the longest decay time. At low energies too much of the timing information is lost, and this method does not perform well. However, the timing of all photons does contain sufficient information. If we use sufficiently fast PMTs, have a large enough bandwidth in the Front End electronics, and avoid reflections then we should reach a background rejection better than 10 −2 even at 2 keV ee .In our Decay Time Measurement (DTM) method the decay curves are compared with a model on an event by event basis. Statistically this is independent from the charge over light ('S2/S1') cut normally applied in Dual Phase detectors. Applying both rejection mechanisms a LXeTPC can become 'quasi background free'. K: Detector modelling and simulations I (interaction of radiation with matter, interaction of photons with matter, interaction of hadrons with matter, etc); Detector modelling and simulations II (electric fields, charge transport, multiplication and induction, pulse formation, electron emission, etc) 1Corresponding author.

We model and simulate the microscopic electromagnetic fields induced by ion currents passing through nanochannels based on membrane currents data obtained by A. L. Hodgkin and A. F. Huxley in their experiments on squid giant axons. We find that compared with magnetic field, electric field affects ion motion much more considerably, and we further discuss the effect of such electric fields on the spread of Na + concentration and the simulation shows that the field remarkably accelerates the diffusion process of ions left the channel.