985 research outputs found

    Symmetry restoration and quantumness reestablishment

    Get PDF
    A realistic quantum many-body system, characterized by a generic microscopic Hamiltonian, is accessible only through approximation methods. The mean field theories, as the simplest practices of approximation methods, commonly serve as a powerful tool, but unfortunately often violate the symmetry of the Hamiltonian. The conventional BCS theory, as an excellent mean field approach, violates the particle number conservation and completely erases quantumness characterized by concurrence and quantum discord between different modes. We restore the symmetry by using the projected BCS theory and the exact numerical solution and find that the lost quantumness is synchronously reestablished. We show that while entanglement remains unchanged with the particle numbers, quantum discord behaves as an extensive quantity with respect to the system size. Surprisingly, discord is hardly dependent on the interaction strengths. The new feature of discord offers promising applications in modern quantum technologies.Comment: 17 pages and 3 figure

    Twist-3 light-cone distribution amplitudes of the scalar mesons within the QCD sum rules and their application to the BSB \to S transition form factors

    Full text link
    We investigate the twist-3 light-cone distribution amplitudes (LCDAs) of the scalar mesons a0a_0, K0K^{\ast}_0 and f0f_0 within the QCD sum rules. The QCD sum rules are improved by a consistent treatment of the sizable ss-quark mass effects within the framework of the background field approach. Adopting the valence quark component (qˉ1q2)(\bar{q}_1 q_2) as the dominant structure of the scalar mesons, our estimation for their masses are close to the measured a0(1450)a_0(1450), K0(1430)K^{\ast}_0(1430) and f0(1710)f_0(1710). From the sum rules, we obtain the first two non-zero moments of the twist-3 LCDAs ϕa0s,σ\phi^{s,\sigma}_{a_0}: ξs,a02(4)=0.369  (0.245)\langle \xi_{s,a_0}^{2(4)} \rangle=0.369 \;(0.245) and ξσ,a02(4)=0.203  (0.093)\langle \xi_{\sigma,a_0}^{2(4)} \rangle=0.203 \;(0.093); those of the twist-3 LCDAs ϕK0s,σ\phi_{K^*_0}^{s,\sigma}: ξs,K01(2)=0.004  (0.355)\langle \xi_{s,K^{\ast}_0}^{1(2)} \rangle =0.004\;(0.355) and ξσ,K01(2)=0.018  (0.207)\langle \xi_{\sigma,K^{\ast}_0}^{1(2)} \rangle =0.018\;(0.207); and those of the twist-3 LCDAs ϕf0s,σ\phi_{f_0}^{s,\sigma}: ξs,f02(4)=0.335  (0.212)\langle \xi_{s,f_0}^{2(4)} \rangle=0.335 \;(0.212) and ξσ,f02(4)=0.196  (0.088)\langle \xi_{\sigma,f_0}^{2(4)} \rangle=0.196 \; (0.088), respectively. As an application of those twist-3 LCDAs, we study the BSB \to S transition form factors by introducing proper chiral currents into the correlator, which is constructed such that the twist-3 LCDAs give dominant contribution and the twist-2 LCDAs make negligible contribution. Our results of the BSB \to S transition form factors at the large recoil region q20q^2 \simeq 0 are consistent with those obtained in the literature, which inversely shows the present twist-3 LCDAs are acceptable.Comment: 14 pages, 12 figures, 7 table

    Higher-order solutions to non-Markovian quantum dynamics via hierarchical functional derivative

    Full text link
    Solving realistic quantum systems coupled to an environment is a challenging task. Here we develop a hierarchical functional derivative (HFD) approach for efficiently solving the non-Markovian quantum trajectories of an open quantum system embedded in a bosonic bath. An explicit expression for arbitrary order HFD equation is derived systematically. Moreover, it is found that for an analytically solvable model, this hierarchical equation naturally terminates at a given order and thus becomes exactly solvable. This HFD approach provides a systematic method to study the non-Markovian quantum dynamics of an open system coupled to a bosonic environment.Comment: 5 pages, 2 figure

    2,4-Dichloro-6-nitro­benzoic acid

    Get PDF
    The title compound, C7H3Cl2NO4, was prepared by the reaction of 2,4-dichloro-6-nitro­toluene with 20% HNO3 solution at 430 K. The carboxyl and nitro groups are twisted by 82.82 (12) and 11.9 (2)°, respectively, with respect to the benzene ring. The crystal structure is stabilized by O—H⋯O hydrogen bonding between carboxyl groups and weak C—H⋯O hydrogen bonding between the nitro group and the benzene ring of an adjacent mol­ecule

    A Novel Rough Set Model in Generalized Single Valued Neutrosophic Approximation Spaces and Its Application

    Get PDF
    In this paper, we extend the rough set model on two different universes in intuitionistic fuzzy approximation spaces to a single-valued neutrosophic environment

    Dynamical invariants in non-Markovian quantum state diffusion equation

    Full text link
    We find dynamical invariants for open quantum systems described by the non-Markovian quantum state diffusion (QSD) equation. In stark contrast to closed systems where the dynamical invariant can be identical to the system density operator, these dynamical invariants no longer share the equation of motion for the density operator. Moreover, the invariants obtained with from bi-orthonormal basis can be used to render an exact solution to the QSD equation and the corresponding non-Markovian dynamics without using master equations or numerical simulations. Significantly we show that we can apply these dynamic invariants to reverse-engineering a Hamiltonian that is capable of driving the system to the target state, providing a novel way to design control strategy for open quantum systems.Comment: 6 pages, 2 figure

    Cardioprotective effects of the total flavonoids of Polygonum cuspidatum Sieb. et Zucc. Root extract on experimental myocardial infarction in mice

    Get PDF
    Purpose: To study the cardioprotective effects of the total flavonoids from the roots of Polygonum cuspidatum Sieb. et Zucc. (FHZ) on experimental myocardial infarction in mice.Methods: Ultrasonic-assisted extraction of FHZ was optimized by response surface methodology (RSM) to obtain a higher extraction yield. Myocardial infarction (MI) was established by ligation of the left anterior descending (LAD) branch of the coronary artery in mice. Cardiac troponin T (cTnT), creatine phosphokinase (CPK), lactate dehydrogenase (LDH), lipid peroxide (LPO), malondialdehyde (MDA) and superoxide dismutase (SOD) levels in the serum of mice were assessed by enzyme-linked immunosorbent assay. Furthermore, myocardial infarction size (MIS) was examined by Masson’s Trichrome staining on heart tissues.Results: Optimum extraction conditions of FHZ were as follows: an ethanol concentration of 69.03 %, a liquid-solid ratio of 27.14 g/mL and an extraction time of 30.30 min. The obtained extraction conditions were proven to be accurate and reliable. After treatment with FHZ for 3 and 7 days, the serum level of cTnT in MI mice decreased significantly. Also, the serum levels of CPK, LPO, MDA, and LDH were significantly decreased while SOD level increased in MI mice treated with FHZ. Furthermore, after treatment with FHZ for two weeks, the MIS of MI mice decreased (p < 0.01).Conclusion: RSM is a useful tool to optimize the ultrasonic-assisted extraction conditions for FHZ. Furthermore, FHZ possesses significant cardioprotective effects on experimental myocardial infarction in mice and thus may find application in the clinical management of myocardial infarction.Keywords: Polygonum cuspidatum, Flavonoids, Response surface methodology, Myocardial infarction, Cardioprotectiv

    Crystal engineered acid–base complexes with 2D and 3D hydrogen bonding systems using p-hydroxybenzoic acid as the building block

    Get PDF
    p-Hydroxybenzoic acid (p-HOBA) was selected as the building block for self-assembly with five bases, i.e., diethylamine, tert-butylamine, cyclohexylamine, imidazole and piperazine, and generation of the corresponding acid–base complexes 1–5. Crystal structure analyses suggest that proton-transfer from the carboxyl hydrogen to the nitrogen atom of the bases can be observed in 1–4, while only in 5 does a solvent water molecule co-exist with p--HOBA and piperazine. With the presence of O–H···O hydrogen bonds in 1–4, the deprotonated p-hydroxybenzoate anions (p-HOBAA–) are simply connected each other in a head-to-tail motif to form one-dimensional (1D) arrays, which are further extended to distinct two-dimensional (2D) (for 1 and 4) and three-dimensional (3D) (for 2 and 3) networks via N–H···O interactions. While in 5, neutral acid and base are combined pair-wise by O–H···N and N–H···O bonds to form a 1D tape and then the 1D tapes are sequentially combined by water molecules to create a 3D network. Some interlayer or intralayer C–H···O, C–H···p and p×××p interactions help to stabilize the supramolecular buildings. Melting point determination analyses indicate that the five acid–base complexes are not the ordinary superposition of the reactants and they are more stable than the original reactants
    corecore