Coupled-channel pseudo-potential description of the Feshbach resonance in two dimensions

We derive pseudo-potentials that describe the scattering between two particles in two spatial dimensions for any partial wave m, whose scattering strength is parameterized in terms of the m-dependent phase shift. Using our m=0 pseudo-potential, we develop a coupled channel model with 2D zero-range interactions, which describes the two-body physics across a Feshbach resonance. Our model predicts the scattering length, the binding energy and the "closed channel molecular fraction" of two particles; these observables can be measured in experiments on ultracold quasi-2D atomic Bose and Fermi gases with present-day technology.Comment: 4 pages, 3 figure

Pseudo-potential treatment of two aligned dipoles under external harmonic confinement

Dipolar Bose and Fermi gases, which are currently being studied extensively experimentally and theoretically, interact through anisotropic, long-range potentials. Here, we replace the long-range potential by a zero-range pseudo-potential that simplifies the theoretical treatment of two dipolar particles in a harmonic trap. Our zero-range pseudo-potential description reproduces the energy spectrum of two dipoles interacting through a shape-dependent potential under external confinement very well, provided that sufficiently many partial waves are included, and readily leads to a classification scheme of the energy spectrum in terms of approximate angular momentum quantum numbers. The results may be directly relevant to the physics of dipolar gases loaded into optical lattices.Comment: 9 pages, 4 figure

Multi-component states for trapped spin-1 Bose-Einstein Condensates in the presence of magnetic field

In presence of a magnetic field, the multi-component ground states appear for trapped spin-1 Bose-Einstein condensates for both ferromagnetic and anti-ferromagnetic types of spin-spin interaction. We aim to produce an accurate analytical description of the multi-component states which is of fundamental importance. Despite being in the so-called regime of Thomas-Fermi approximation (condensates with large particle number), the scenario of multi-component states is problematic under this approximation due to large variation in densities of the sub-components. We generalize the variational method that we have introduced in the article [Eur. Phys. J. Plus 137, 547 (2022)] to overcome this limitation of T-F approximation. We demonstrate that, the variational method is crucial in giving a proper analytical description of the multi-component states. The results obtained from the variational method are also backed by numerical simulation. A comparison of the strength of our variational method, which is multi-modal, with that of single-mode approximation is also presented in this paper to demonstrate a marked improvement in accuracy over single-mode approximation.Comment: 14 pages, 9 figure

A variational approach for the ground state profile of a trapped spinor-BEC: A detailed study of phase transition in spin-1 condensate at zero magnetic field

The ground state of a spin-1 Bose-Einstein condensate is selected based on the most energetically stable stationary state. It is well known that for the homogeneous condensate linear and quadratic term plays an important role to lift the degeneracy among the stationary states, giving a rich phase diagram. In this article, we investigate the ground state in absence of linear and quadratic Zeeman terms under realistic trapping potential. The spin-dependent interaction strength plays a key role in favoring one of the stationary state to have the lowest energy and thus producing the ground state of the system. We notice that the Thomas-Fermi approximated results predict that for anti-ferromagnetic condensates the energy difference between the competing stationary states is really small, requiring further analysis considering the full profile of the condensate. Thus, for the purpose of further refining results, we introduce a variational method which provides the full number density profile of the condensate with very good accuracy even for small condensates in 3-dimensional isotropic harmonic confinement as well as in effective 1-dimensional harmonic trapping. Then we compare all the relevant physical parameters with those of Thomas-Fermi results.Comment: 17 pages, 13 figure

Au9+ swift heavy ion irradiation of Zn[CS(NH2)2]3SO4 crystal: Crystalline perfection and optical properties

The single crystal of tris(thiourea)zinc sulphate (Zn[CS(NH2)2]3SO4) was irradiated by 150 MeV Au9+ swift heavy ions and analyzed in comparison with pure crystal for crystalline perfection and optical properties. The Fourier transform infrared and x-ray powder diffraction inferred that swift ions lead the disordering and breaking of molecular bonds in lattice without formation of new structural phases. High resolution X-ray diffraction (HRXRD) revealed the abundance of point defects, and formation of mosaics and low angle grain boundaries in the irradiated region of crystal. The swift ion irradiation found to affect the lattice vibrational modes and functional groups significantly. The defects induced by heavy ions act as the color centers and resulted in enhance of photoluminescence emission intensity. The optical transparency and band gap found to be decreased.Comment: 7 page

Low-energy resonances and bound states of aligned bosonic and fermionic dipoles

The low-energy scattering properties of two aligned identical bosonic and identical fermionic dipoles are analyzed. Generalized scattering lengths are determined as functions of the dipole moment and the scattering energy. Near resonance, where a new bound state is being pulled in, all non-vanishing generalized scattering lengths diverge, with the $a_{00}$ and $a_{11}$ scattering lengths being dominant for identical bosons and identical fermions, respectively, near both broad and narrow resonances. Implications for the energy spectrum and the eigenfunctions of trapped two-dipole systems and for pseudo-potential treatments are discussed.Comment: 4 pages, 4 figure

Unbounded Sharing of Nonlocality Using Projective Measurements

It is a common perception that a sharp projective measurement in one side of the Bell experiment destroys the entanglement of the shared state, thereby preventing the demonstration of sequential sharing of nonlocality. In contrast, we introduce a local randomness-assisted projective measurement protocol, enabling the sharing of nonlocality by an arbitrary number of sequential observers (Bobs) with a single spatially separated party Alice. Subsequently, a crucial feature of the interplay between the degrees of incompatibility of observables of both parties is revealed, enabling the unbounded sharing of nonlocality. Our findings, not only offer a new paradigm for understanding the fundamental nature of incompatibility in demonstrating quantum nonlocality but also pave a new path for various information processing tasks based on local randomness-assisted projective measurement

Structural analysis of 105 K Basin monorails

Structural analysis of 105 K Basin monorails. The analysis addresses all monorails in the K basin and documented the load carrying capacity of each monorail

The non-linear dynamics of vortices subjected to correlated and random pinning disorders in a quasi-2D superconductor

Understanding the dynamics of vortex matter subjected to random and correlated pinning disorders in layered superconductors remains a topic of considerable interest. The dynamical behavior of vortices in these systems shows a rich variety of effects due to many competing interactions. Here, we study the ac response of as-grown as well as heavy-ion-irradiated Tl2Ba2CaCu2O8 (Tl-2212) thin films by using a micro Hall-probe susceptometer. We find that the dynamics of vortices in the high-temperature, low-field regime of the H-T phase diagram investigated here depends on the nature of pinning defects. While the decay of screening currents J(t) indicates a glassy behavior in both types of samples, the nature of the glassy phase is different in the two cases. Samples with columnar defects show distinct signature of a Bose glass in the measurement of J(t) and the angular dependence of the irreversibility field (B irr)