Spins-based Quantum Otto Engines and Majorisation

The concept of majorisation is explored as a tool to characterize the performance of a quantum Otto engine in the quasi-static regime. For a working substance in the form of a spin of arbitrary magnitude, majorisation yields a necessary and sufficient condition for the operation of the Otto engine, provided the canonical distribution of the working medium at the hot reservoir is majorised by its canonical distribution at the cold reservoir. For the case of a spin-1/2 interacting with an arbitrary spin via isotropic Heisenberg exchange interaction, we derive sufficient criteria for positive work extraction using the majorisation relation. Finally, local thermodynamics of spins as well as an upper bound on the quantum Otto efficiency is analyzed using the majorisation relation.Comment: RevTex4-2, 24 pages, six figure

A Comprehensive Review of Literature and Exploration on Library Security System

The most important component in libraries is the security system. which is responsible to keep up the library safe and secure against any type of threat. Libraries today use the newest security systems available, which are very beneficial and effective for them. In light of this, the present study is carried out for literature review on the use and applications of security system in libraries. The paper aims to evaluate numerous aspects of security system for libraries, including their benefits and drawbacks. The paper will also be revealed that what are the challenging factor which libraries facing for the efficient implementation of security tools and methods. This will be help for library professional for the deep understanding of security setup and how they can use these by overcoming challenging factors

Energy-gap modulation and majorization in three-level quantum Otto engine

A three-level quantum system having two energy gaps presents a nontrivial working medium for a quantum heat engine. Our focus lies in understanding the constraints on the ability to modulate these gaps relative to the changes in probability distributions at the two given heat reservoirs. It is seen that an Otto engine in the quasistatic limit is feasible if at least one energy gap shrinks during the first quantum adiabatic stage. We analyze operating conditions under different variations of the gaps, revealing that a definite majorization relation between the hot and cold distributions serves as a sufficient criterion for the engine when both gaps are shrinking. Further, Otto efficiency is enhanced in case majorization holds. On the other hand, majorization becomes a necessary condition when only one of the gaps is shrinking. In the special case where one gap remains fixed, majorization is both necessary and sufficient for engine operation. For an $n$-level system, we note that a well defined change in energy gaps aligns with the majorization relation, thus characterizing the operation of the engine.Comment: 24 pages, 6 figure

Sufficient conditions for the uniqueness of solution of the weighted norm minimization problem

Prior support constrained compressed sensing, achieved via the weighted norm minimization, has of late become popular due to its potential for applications. For the weighted norm minimization problem, $$min \|x\|_{p,w} \text{ subject to } y=Ax, \; p=0,1, \text{ and } w \in [0,1],$$ uniqueness results are known when $w=0,1$. Here, $\|x\|_{p,w}=w\|x_T\|_p+\|x_{T^c}\|_p, \; p=0,1$ with $T$ representing the partial support information. The work reported in this paper presents the conditions that ensure the uniqueness of the solution of this problem for general $w \in [0,1]$.Comment:

A quick and selective rhodamine based “smart probe” for “signal-on” optical detection of Cu²⁺ and Al³⁺ in water, cell imaging, computational studies and solid state analysis

A novel rhodamine hydrazone 1 has been synthesized by the condensation of rhodamine B hydrazide with allylsalicylaldehyde and has been fully characterized using various physicochemical techniques including single crystal XRD. Probe 1 can detect Cu2+ and Al3+ ions in aqueous media and displays a turn-on response in absorbance with a high degree of selectivity amongst other common interfering analytes. Al3+ ions lead to fluorescence enhancementby the opening of the spirolactum ring resulting in chelation enhanced fluorescence. DFT and TDDFT calculations support the experimental results. The 1-Al3+ ensemble acts as secondary sensor for pyrophosphate anion due to metal ion induced decomplexation resulting in a low detection limit. Probe 1 can be utilized for bio imaging and displays morphological transformations from crystalline to amorphous state with associated color changes due to mechanical switching. In the solid state, probe 1 displays distinct color changes with emission at different wavelengths in particular Al3+ and Hg2+result in a red shift of the CIE-diagram. While the band gap of probe 1can be tuned from 2.08 eV to 1.60 eV.Probe 1 meets many real-world-challenges in that it is prepared using simple synthetic methods, produces fast and distinct response towards multiple-ions, observed by the “naked eye” in solution and on a TLC plate, and can be exploited for binary data storage