Quasiprobability distributions in open quantum systems: spin-qubit systems

Quasiprobability distributions (QDs) in open quantum systems are investigated for $SU(2)$, spin like systems, having relevance to quantum optics and information. In this work, effect of both quantum non-demolition (QND) and dissipative open quantum systems, on the evolution of a number of spin QDs are investigated. Specifically, compact analytic expressions for the $W$, $P$, $Q$, and $F$ functions are obtained for some interesting single, two and three qubit states, undergoing general open system evolutions. Further, corresponding QDs are reported for an N qubit Dicke model and a spin-1 system. The existence of nonclassical characteristics are observed in all the systems investigated here. The study leads to a clear understanding of quantum to classical transition in a host of realistic physical scenarios. Variation of the amount of nonclassicality observed in the quantum systems, studied here,are also investigated using nonclassical volume.Comment: 23 pages 13 figure

Adiabatic Logic-in-Memory Architecture

An adiabatic logic-in-memory based complementary metal- oxide-semiconductor/magnetic-tunnel-junction (ALiM CMOS/MTJ) circuit utilizes an adiabatic logic based pre- charged sense amplifier (PCSA) to recover energy from its output load capacitors. The ALiM CMOS/MTJ includes a non-volatile magnetic-tunnel-junction (MTJ) based memory. The ALiM CMOS/MTJ also includes a dual rail complementary metal-oxide-semiconductor (CMOS) logic that performs logic operations in association with the MTJ, and thereby generates logic outputs based on logic inputs. The ALiM CMOS/MTJ also includes the adiabatic PCSA, which is operatively coupled to the dual rail CMOS logic. The adiabatic logic based PCSA includes PCSA circuitry for which an input is a multi-phase power clock, and a charge recovery circuit having the output load capacitors. The charge recovery circuit is operatively coupled to the PCSA circuitry such that the ALiM CMOS/MTJ circuit uses the power clock to recover energy from the output load capacitors

Perfect initialization of a quantum computer of neutral atoms in an optical lattice of large lattice constant

We propose a scheme for the initialization of a quantum computer based on neutral atoms trapped in an optical lattice with large lattice constant. Our focus is the development of a compacting scheme to prepare a perfect optical lattice of simple orthorhombic structure with unit occupancy. Compacting is accomplished by sequential application of two types of operations: a flip operator that changes the internal state of the atoms, and a shift operator that moves them along the lattice principal axis. We propose physical mechanisms for realization of these operations and we study the effects of motional heating of the atoms. We carry out an analysis of the complexity of the compacting scheme and show that it scales linearly with the number of lattice sites per row of the lattice, thus showing good scaling behavior with the size of the quantum computer.Comment: 18 page

Continuous variable direct secure quantum communication using Gaussian states

Continuous variable one-way and controlled-two-way secure direct quantum communication schemes have been designed using Gaussian states. Specifically, a scheme for continuous variable quantum secure direct communication and another scheme for continuous variable controlled quantum dialogue are proposed using single-mode squeezed coherent states. The security of the proposed schemes against a set of attacks (e.g., Gaussian quantum cloning machine and intercept resend attacks) has been proved. Further, it is established that the proposed schemes do not require two-mode squeezed states which are essential for a set of existing proposals. The controlled two-way communication scheme is shown to be very general in nature as it can be reduced to schemes for various relatively simpler cryptographic tasks like controlled deterministic secure communication, quantum dialogue, quantum key distribution. In addition, it is briefly discussed that the proposed schemes can provide us tools to design quantum cryptographic solutions for several socioeconomic problems.Comment: Continuous Variable protocols are designed for one-way and controlled-two-way secure direct quantum communication using single-mode squeezed coherent state

Continuous variable B92 quantum key distribution protocol using single photon added and subtracted coherent states

In this paper, a continuous variable B92 quantum key distribution (QKD) protocol is proposed using single photon added and subtracted coherent states, which are prepared by adding and subsequently subtracting a single photon on a coherent state. It is established that in contrast to the traditional discrete variable B92 protocol, this protocol for QKD is intrinsically robust against the unambiguous state discrimination attack, which circumvents the requirement for any uninformative states or entanglement used in corresponding discrete variable case as a remedy for this attack. Further, it is shown that the proposed protocol is intrinsically robust against the eavesdropping strategies exploiting classical communication during basis reconciliation, such as beam splitter attack. Security against some individual attacks, key rate, and bit-error rate estimation for the proposed scheme are also provided. Specifically, the proposed scheme ensures very small bit-error rate due to properties of the states used. Thus, the proposed scheme is shown to be preferable over the corresponding discrete variable B92 protocol as well as some similar continuous variable quantum key distribution schemes.Comment: A continuous variable version of B92 protocol for QKD is proposed and shown that it has some advantages over traditional B92 protoco

Development of a time series-based methodology for estimation of large-area soil wetness over India using IRS-P4 microwave radiometer data

Soil moisture is a very important boundary parameter in numerical weather prediction at different spatial and temporal scales. Satellite-based microwave radiometric observations are considered to be the best because of their high sensitivity to soil moisture, apart from possessing all-weather and day-night observation capabilities with high repetitousness. In the present study, 6.6-GHz horizontal-polarization brightness temperature data from the Multifrequency Scanning Microwave Radiometer (MSMR) onboard the Indian Remote Sensing Satellite IRS-P4 have been used for the estimation of large-area-averaged soil wetness. A methodology has been developed for the estimation of soil wetness for the period of June-July from the time series of MSMR brightness temperatures over India. Maximum and minimum brightness temperatures for each pixel are assigned to the driest and wettest periods, respectively. A daily soil wetness index over each pixel is computed by normalizing brightness temperature observations from these extreme values. This algorithm has the advantage that it takes into account the effect of time-invariant factors, such as vegetation, surface roughness, and soil characteristics, on soil wetness estimation. Weekly soil wetness maps compare well to corresponding weekly rainfall maps depicting clearly the regions of dry and wet soil conditions. Comparisons of MSMR-derived soil wetness with in situ observations show a high correlation (R>0.75), with a standard error of the soil moisture estimate of less than 7% (volumetric unit) for the surface (0-5 cm) and subsurface (5-10 cm) soil moisture

Impact of Dapagliflozin Adjunctive Therapy on Progression of Chronic Kidney Disease in Patients with Type 2 Diabetes and CKD Stage 2–5: A systematic review and meta-analysis

This meta-analysis was conducted by searching PubMed, Scopus, Cochrane, Ovid till November 2022 for randomized controlled trials (RCTs) that utilized dapagliflozin 10 mg as adjunctive therapy in patients with T2DM and CKD stage 2-5 and reported its renal efficacy in terms of mean change in estimated glomerular filtration rate (eGFR) and urinary albumin creatinine ratio (UACR) from baseline. From 1682 identified records, nine studies representing 13,057 patients were selected for this study. Pooled estimate of five studies showed that dapagliflozin did not affect eGFR but caused significantly less chronic eGFR decline than placebo in two studies [Mean difference (MD) +2.74 (95% CI: 1.55, 3.92; p < 0.00001)]. Pooled estimate of four studies showed that dapagliflozin significantly reduced UACR[-23.99 % MD (95% CI - 34.82, -13.15, p-value < 0.0001; = 0%)]. This confirms that long-term dapagliflozin use significantly attenuates eGFR decline and reduces albuminuria in T2DM and CKD stages 2-5 patients. Keywords: Chronic kidney disease, Dapagliflozin, Estimated GFR, eGFR, SGLT2 inhibitors, Type 2 diabetes mellitus, Urine albumin to creatinine ratio, UACR

"It also taught me a lot about myself" : a qualitative exploration of how men understand eating disorder recovery

Eating Disorders (ED) are relatively common in the general population. However, perceived as “female disorders”, EDs in men are often overlooked. Although recovery is often seen as the ideal end goal of ED, there is no single universal definition of recovery. Recovery can be defined in terms of: physical changes, behavioural changes, psychological (cognitive and emotional) and improved quality of life. There is very little research exploring how people with ED define/ understand what recovery is and there is even less research involving men with ED. Therefore, the aim of this study was to explore recovery from men’s perspective