We develop a method for calculating multichannel wavefunctions in the spirit of quantum defect theory, based on numerically calculated reference functions. We benchmark the method by calculating cold collisional properties of 85Rb and 6Li in the presence of external magnetic fields tuned across specific s-wave Feshbach resonances and thereby reproducing known results. We then apply the method to calculate experimentally observed d-wave Feshbach resonance in 87Rb-85Rb cold collisions. Our numerical results for this d-wave resonance show good agreement with the experimental observations. The method is applicable to arbitrary interaction potentials and to any energy range near the scattering threshold. The implementation of our method to any multichannel two-body scattering problem is straightforward.
Ice growth phenomena have attracted attention because water and ice are omnipresent in the environment and play significant roles in different natural processes. In this work we report the results of systematic molecular dynamics study of ice growth on different planes of hexagonal ice. First, we define the layer region for three planes by carefully analysing water density along the growth directions and by tracking the time-dependent growth processes of different sub-layers. Next, we observe that the nature of the growth process on prismatic planes follow conventional three-dimensional growth mechanism without cubic ice formation across different supercooling. On the basal plane, growth happens in a layer-by-layer fashion at low supercooling. We find that the formation of each layer is associated with a competition between hexagonal and cubic phases of ice at the initial stage. Such a competition ultimately gives rise to the halting with random waiting times in growth on the basal plane. Additionally, no in-layer mixing of hexagonal and cubic ices is observed at low supercooling. At high supercooling, growth on the basal plane loses its layer-by-layer character, with in-layer defect formation that shows directionality.
We suggest a simple generalization of Chapman–Kolmogorov equation used to describe many stochastic Markov processes in natural sciences. This generalization is based on the consideration that a random walker slips before reaching his next step. We discuss two exactly solvable cases. First, the bidirectional random walk with a slip which leads to familiar Ornstein–Uhlenbeck process. Second, unidirectional random walk with a slip, an unexplored area to the best of our knowledge. We show interesting pulse-like spatio-temporal evolution without spreading for this stochastic process in the long wavelength limit.
We investigate the impact of a dark matter density spike surrounding the Milky Way's supermassive black hole (SMBH) on the detectability of Singlino-dominated neutralino dark matter within the Next-to-Minimal Supersymmetric Standard Model (NMSSM). Similar density enhancements, or mini-spikes, around stellar-mass black holes (sBHs), have also been considered. Such a dark matter (DM) candidate typically produces weak indirect detection signals in conventional dark matter halos. Additionally, a Singlino-like lightest supersymmetric particle (LSP) is very difficult to probe at the LHC or through the direct DM search experiments. On top of that, recent observation of the LUX-ZEPLIN 248 keV Nuclear-Recoil Event may hint towards a DM that can be accommodated by a Singlino with mass more than 200 GeV. Keeping these in consideration, we examine the prospects for detecting these sub-TeV dark matter scenarios through gamma-ray observations of the regions surrounding the SMBH Sgr A^∗ and the sBH in the low-mass X-ray binary XTE J1118+480.
This paper investigates the dynamical phases of Floquet Conformal Field Theories (CFTs) in space-time dimensions greater than two. Building upon our previous work [1] which introduced quaternionic representations for studying Floquet dynamics in higher dimensional CFTs, we now explore more general square pulse drive protocols that go beyond a single SU(1,1) subgroup. We demonstrate that, for multi-step drive protocols, the system exhibits distinct dynamical phases characterized by the nature of the eigenvalues of the quaternionic matrix representing time evolution in a single cycle, leading to different stroboscopic responses. Our analysis establishes a fundamental geometric interpretation where these dynamical phases directly correspond to the presence or absence of Killing horizons in the base space of the CFT and in a higher dimensional AdS space on which a putative dual lives. The heating phase is associated with a non-extremal horizon, the critical phase with an extremal horizon which disappears in the non-heating phase. We develop perturbative approaches to compute the Floquet Hamiltonians in different regimes and show, how tuning drive parameters can lead to horizons, providing a geometric framework for understanding heating phenomena in driven conformal systems.
