Radio frequency spectroscopy of the attractive Hubbard model in a trap

Attractive interaction between fermions can lead to pairing and superfluidity in an optical lattice. In contrast to the `continuum', on a lattice the trap induced density variation can generate a non monotonic profile of the pairing amplitude, and completely modify the spectral signatures of any possible pseudogap phase. Using a tool that fully captures the inhomogeneity and strong thermal fluctuations, we demonstrate how the crucial radio frequency signatures of pairing are `inverted' in a trapped attractive fermion lattice compared to the traditional continuum case. These features would be central in interpreting any spectroscopic hint of fermion pairing and superfluidity.Comment: this article supersedes arXiv:1104.491

Evidence of linear and cubic Rashba effect in non-magnetic heterostructure

The LaAlO3/KTaO3 system serves as a prototype to study the electronic properties that emerge as a result of spin-orbit coupling. In this article, we have used first-principles calculations to systematically study two types of defect-free (0 0 1) interfaces, which are termed as Type-I and Type-II. While the Type-I heterostructure produces a two-dimensional electron gas, the Type-II heterostructure hosts an oxygen-rich two-dimensional hole gas at the interface. Furthermore, in the presence of intrinsic spin-orbit coupling, we have found evidence of both cubic and linear Rashba interactions in the conduction bands of the Type-I heterostructure. On the contrary, there is spin-splitting of both the valence and the conduction bands in the Type-II interface, which are found to be only linear Rashba type. Interestingly, the Type-II interface also harbours a potential photocurrent transition path, making it an excellent platform to study the circularly polarized photogalvanic effect

Rashba splitting in polar-nonpolar sandwich heterostructure : A DFT Study

In this study, we employ density functional theory (DFT) based first-principles calculations to investigate the spin-orbit effects in the electronic structure of a polar-nonpolar sandwich heterostructure namely LAO$_{2.5}$/STO$_{5.5}$/LAO$_{2.5}$. Our focus on the Ti-3d bands reveals an inverted ordering of the STO-$\rm t_{2g}$ orbital near the n-type interface, consistent with earlier experimental work. In contrast, toward the p-type interface, the orbital ordering aligns with the natural ordering of STO orbitals, influenced by crystal field splitting. Interestingly, we have found a strong inter-orbital coupling between $t_{2g}$ and $e_g$ orbital, which has not been reported earlier in $\rm SrTiO_3$ based 2D system. Additionally, our observations highlight that the cubic Rashba splitting in this system surpasses the linear Rashba splitting, contrary to experimental findings. This comprehensive analysis contributes to a refined understanding of the role of orbital mixing in Rashba splitting in the sandwich oxide heterostructures

Long range correlations in a 97% excitonic one-dimensional polariton condensate

We report on the realization of an out-of-equilibrium polariton condensate under pulsed excitation in a one-dimensional geometry. We observe macroscopic occupation of a polaritonic mode with only 3% photonic fraction, and a nature strikingly close to that of a bare exciton condensate. With the help of this tiny photonic fraction, the condensate is found to display first-order coherence over distances as large as 10 microns. Based on a driven-dissipative mean field model, we find that the correlations length is limited by the effects of a shallow disorder under non-equilibrium conditions.Comment: 5 pages, 3 figure

Electrical conductivity degradation of fatigued carbon black reinforced natural rubber composites: Effects of carbon nanotubes and strain amplitudes

The fatigue of rubber products is usually accompanied by undesirable transformation in their properties. The present work was dedicated to the investigation of consequences of fatigue loading on volume electric conductivity of natural rubber (NR) reinforced with 30 phr of fillers composed from various weight combinations of carbon nanotubes (CNTs) and carbon black (CB). Special attention was paid to study the influence of CNTs content on residual electric conductivity and a possible mechanism of fatigue driven rearrangement of hybrid filler network inside of rubber matrix was propounded forward. An increase in the CNTs content over the complete range of concentrations, enhanced the conductivity of fabricated samples up to two orders of magnitude in comparison to rubber compounds without CNTs. All the samples were subjected to harmonic sinusoidal loading at a frequency of 5 Hz up to 10(5) loading cycles at three different strains of 0.1, 0.25 and 0.5. Despite very little transformation in the polymer matrix, fatigue caused a progressive degradation of conductivity with an increase in applied strain. It was also found that with the addition and a subsequent increase in the concentration of CNTs, the undesirable reduction of conductivity was significantly arrested. This novel finding added another number to the list of the outstanding properties of CNTs.Operational Program Research and Development for Innovations - European Regional Development FundEuropean Union (EU); national budget of the Czech Republic [CZ.1.05/2.1.00/19.0409]; Ministry of Education, Youth and Sports of the Czech Republic - Program NPU I [LO1504]; [IGA/CPS/2019/001

Influence of non-genetic factors on body weight in Black Bengal goats maintained under field condition

Data recorded on 10,148 Black Bengal kids maintained at farmer’s herds in different districts of West Bengal from 2008 to 2019 were used to study the effect of non-genetic factors on body weight from birth to 12 months of age. The data were analysed using least squares technique. The effect of year of kidding on body weight of Black Bengal kids at different ages was significant (p<0.05). Influence of season and parity of the dam had significant effect (p<0.05) on body weight of kids from birth to 6 months of age. Sex of the kid significantly influenced body weight from birth to 12 months of age. Effect of types of birth on body weight at different ages up to 12 months of age of Black Bengal kids were significant (p<0.05). Significantly higher body weight at birth was recorded in single born kid, followed by twin, triplets and so on

Exciton-polaritons gas as a nonequilibrium coolant

Using angle-resolved Raman spectroscopy, we show that a resonantly excited ground-state exciton-polariton fluid behaves like a nonequilibrium coolant for its host solid-state semiconductor microcavity. With this optical technique, we obtain a detailed measurement of the thermal fluxes generated by the pumped polaritons. We thus find a maximum cooling power for a cryostat temperature of $50$K and below where optical cooling is usually suppressed, and we identify the participation of an ultrafast cooling mechanism. We also show that the nonequilibrium character of polaritons constitutes an unexpected resource: each scattering event can remove more heat from the solid than would be normally allowed using a thermal fluid with normal internal equilibration.Comment: 5 pages, 3 figures + supplemental materia