Effect of magnetic field on the long-time dynamics of two charged coupled harmonic oscillators in the presence of a common heat bath

In this paper, the moderately long-time behaviours of the position autocorrelation, position velocity correlation and velocity autocorrelation functions for two charged coupled harmonic oscillators connected to a heat bath are derived in the presence of a magnetic field via the Quantum Langevin equation. It is seen that at long times the correlation functions at T->0 exhibit a power law decay with the coefficients of the power laws being completely different for the two masses that affect the overall trends of the decays of the correlation functions. The effect of the bath-induced force on mass m1 mediated by the interaction of m2 with the common heat bath is studied and the results are highlighted in the presence of an external magnetic field. This brings out the distinctness of the coupled oscillator scenario from the independent single oscillator model studied earlier in the literature. The results in the absence of a magnetic field are also presented, which are extremely important for analyzing the dynamics of atoms in protein molecules at low temperatures.Comment: 12 pages; 7 figure

Decoherence and the ultraviolet cutoff: non-Markovian dynamics of a charged particle in a magnetic field

We derive a non-Markovian master equation for a charged particle in a magnetic field coupled to a bath and study decoherence by analysing the temporal decay of the off-diagonal elements of the reduced density matrix in the position basis. The coherent oscillations characterised by the cyclotron frequency get suppressed as a result of decoherence due to coupling with the environment. We consider an Ohmic bath with three distinct models for the high-frequency cutoff for the spectral density of the bath and compare the three cases. As expected, the three cutoff models converge in the limit of the uppermost frequency of the bath tending to infinity. We notice a dramatic slowing down of loss of coherence in the low-temperature limit dominated by zero point quantum fluctuations compared to the high-temperature classical limit dominated by thermal fluctuations. We also go beyond the Ohmic model and study super-Ohmic and sub-Ohmic baths with the spectral densities deviating from a linear dependence on the frequency. Our results are testable in a state of the art cold atom laboratory.Comment: 21 pages, 4 figure

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

Inventory of mammals in protected reserves and natural habitats of Tripura, northeast India with notes on existing threats and new records of Large Footed Mouse-eared Bat and Greater False Vampire Bat

Twenty-four species representing 21 genera, 16 families and 7 orders of mammals were recorded in the Tripura state, northeast India, from an inventory done from 2006 to 2012. Ten of these species were found in wildlife sanctuaries as well as in primary forests. Four species were recorded exclusively from the wildlife sanctuaries and ten species were recorded only from primary forests. Order Primates was the most diverse group represented by 6 species from 4 genera in 3 families. Frequency sightings data showed that 11 species were rare, 2 species were occasional, one species was frequent, and another 10 species were common. Two species, Large-footed Mouse-eared Bat, Myotis sp., and Greater False Vampire Bat, Megaderma lyra, are new records from the study area.  Overall, 23 of the 24 species recorded are listed in the IUCN Red List, 14 species are listed in CITES, and 14 species are protected under the Indian Wildlife Protection Act, 1972. Threats being faced by many of the recorded mammals from human encroachments are highlighted

Mono-, tri- and polynuclear copper(II) complexes of Schiff-base ligands: Synthesis, characterization and catalytic activity towards alcohol oxidation

Three new copper(ii) complexes with different Schiff-base ligands, namely, [Cu(L1)Cl2] (1), [Cu3(L2)2Cl4] (2) and [Cu(L3)N3]n (3) where L1 = 2-morpholino-N-(pyridin-2-ylmethylene)ethanamine, HL2 = 4-bromo-2-((2-morpholinoethylimino)methyl)phenol and HL3 = 4-chloro-2-((2-(dimethylamino)ethylimino)methyl)phenol, have been synthesized and characterized by elemental analysis, standard spectroscopic methods, cyclic voltammometry and single crystal X-ray diffraction analysis. The X-ray diffraction analysis confirms the formation of mononuclear (1), trinuclear (2) and polynuclear (3) complexes. These complexes have been applied as catalysts for alcohol oxidation reactions using tert-butyl hydroperoxide (TBHP) as the terminal oxidant under mild conditions. The catalytic reaction mixture has been analyzed by gas chromatography and it shows that the mononuclear complex has the highest conversion while the other two complexes exhibit moderate catalytic activities. The corresponding aldehyde has been obtained as the sole product. The obtained catalysis results have been corroborated with electrochemical studies

Construction of an Efficient Overlay Multicast Infrastructure for Real-Time Applications

We consider an overlay architecture where service providers deploy a set of service nodes (called MSNs) in the network to efficiently implement media-streaming applications. These MSNs are organized into an overlay and act as application-layer multicast forwarding entities for a set of clients. We present

Probing octupolar hidden order via Janus impurities

Abstract Quantum materials with non-Kramers doublets are a fascinating venue to realize multipolar hidden orders. Impurity probes which break point group symmetries, such as implanted muons or substitutional impurities, split the non-Kramers degeneracy and exhibit a Janus-faced influence in such systems: they can destroy the very order they seek to probe. Here, we explore this duality in cubic osmate double perovskites which are candidates for exotic d-orbital octupolar order competing with quadrupolar states. Using ab initio computations, Landau theory, and Monte Carlo simulations, we show that Janus impurities induce local strain fields, nucleating quadrupolar puddles and suppressing the octupolar T c . At the same time, strains mix the non-Kramers doublet with an excited magnetic triplet, creating parasitic dipole moments which directly expose the hidden octupolar order parameter. Our work unravels this Janus duality in recent impurity nuclear magnetic resonance (NMR) experiments, with important implications for uncovering hidden order in diverse multipolar materials

A turn-on fluorescent chemosensor for Zn2+ ion: X-ray structure and application in cell imaging study

The selective fluorescence zinc(II) sensing properties of a Schiff-base compound, 2-methoxy-6-(2-morpholinoethyliminomethyl)phenol (HL) have been explored. The emission intensity of HL in the presence of one equivalent of Zn2+ ion increases by about 25 times. Several other metal ions, except Cd2+ and Ni2+, have not been able to increase the emission intensity of HL significantly. The quantum yield and life-time of HL have also been increased in the presence of Zn2+ ions. The enhancement in fluorescence intensity of HL is mainly due to the restriction of ESIPT, CHEF and PET on complex formation. HL forms a complex with Zn2+ in 1:1 ratio as evidenced by Job's plot analysis and X-ray single crystal structure determination. Some theoretical calculations have been performed to get a better view on the nature of the observed electronic transitions. The probe has been applied for imaging of DLD-1, human colorectal adenocarcinoma cell