17 research outputs found
A new family of matrix product states with Dzyaloshinski-Moriya interactions
We define a new family of matrix product states which are exact ground states
of spin 1/2 Hamiltonians on one dimensional lattices. This class of
Hamiltonians contain both Heisenberg and Dzyaloshinskii-Moriya interactions but
at specified and not arbitrary couplings. We also compute in closed forms the
one and two-point functions and the explicit form of the ground state. The
degeneracy structure of the ground state is also discussed.Comment: 15 pages, 1 figur
Dynamics of entanglement of bosonic modes on symmetric graphs
We investigate the dynamics of an initially disentangled Gaussian state on a
general finite symmetric graph. As concrete examples we obtain properties of
this dynamics on mean field graphs of arbitrary sizes. In the same way that
chains can be used for transmitting entanglement by their natural dynamics,
these graphs can be used to store entanglement. We also consider two kinds of
regular polyhedron which show interesting features of entanglement sharing.Comment: 14 pages, 11 figures, Accepted for publication in Physics Letters
Caffeine, Coffee, Tea and Risk of Rheumatoid Arthritis: Systematic Review and Dose-Response Meta-analysis of Prospective Cohort Studies
Objective: Prospective cohort studies on coffee, tea and caffeine in relation to the risk of rheumatoid arthritis (RA) have shown conflicting results. The aim of this study was to conduct a dose–response meta-analysis of cohort studies on the association between dietary caffeine, different types of coffee and tea consumption and the risk of RA. Methods: PubMed/Medline, Scopus and EMBASE were searched up to July 2021 to identify relevant studies that had considered different types of coffee (caffeinated or decaffeinated), tea or caffeine exposure with RA as the main, or one of the, outcome(s). Two authors independently screened 742 publications. Finally, five prospective cohort studies were included in our meta-analysis. Pooled relative risks (RRs) were calculated by using a fixed-effects model. We also performed linear and non-linear dose-response analyses to examine the dose-response relations. Results: Comparing extreme categories, we found a positive, significant association between coffee (RR: 1.30; 95% CI: 1.04–1.62; I2 = 0%, n = 5) and decaffeinated coffee (RR: 1.89; 95% CI: 1.35–2.65; I2 = 38.1%, n =3) consumption and risk of RA. One additional cup of coffee consumed per day was associated with an increased risk of RA by 6% (95% CI: 1.02–1.10; I2 = 0%). This increase in the risk of RA for one cup/d of decaffeinated coffee was 11% (95% CI: 1.05–1.18; I2 = 38). No significant association was observed between caffeinated coffee, tea or caffeine intake and the risk of RA. Conclusion: We found that a higher intake of coffee and decaffeinated coffee was associated with increased risk of RA. No significant association between caffeinated coffee, tea or caffeine intake and the risk of RA was observed. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=227665, identifier: CRD42021227665
Entanglement Transfer via XXZ Heisenberg chain with DM Interaction
The role of spin-orbit interaction, arises from the Dzyaloshinski-Moriya
anisotropic antisymmetric interaction, on the entanglement transfer via an
antiferromagnetic XXZ Heisenberg chain is investigated. From symmetrical point
of view, the XXZ Hamiltonian with Dzyaloshinski-Moriya interaction can be
replaced by a modified XXZ Hamiltonian which is defined by a new exchange
coupling constant and rotated Pauli operators. The modified coupling constant
and the angle of rotations are depend on the strength of Dzyaloshinski-Moriya
interaction. In this paper we study the dynamical behavior of the entanglement
propagation through a system which is consist of a pair of maximally entangled
spins coupled to one end of the chain. The calculations are performed for the
ground state and the thermal state of the chain, separately. In both cases the
presence of this anisotropic interaction make our channel more efficient, such
that the speed of transmission and the amount of the entanglement are improved
as this interaction is switched on. We show that for large values of the
strength of this interaction a large family of XXZ chains becomes efficient
quantum channels, for whole values of an isotropy parameter in the region .Comment: 21 pages, 9 figure
Entangled quantum heat engines based on two two-spin systems with Dzyaloshinski-Moriya anisotropic antisymmetric interaction
We construct an entangled quantum heat engine (EQHE) based on two two-spin
systems with Dzyaloshinski-Moriya (DM) anisotropic antisymmetric interaction.
By applying the explanations of heat transferred and work performed at the
quantum level in Kieu's work [PRL, 93, 140403 (2004)], the basic thermodynamic
quantities, i.e., heat transferred, net work done in a cycle and efficiency of
EQHE are investigated in terms of DM interaction and concurrence. The validity
of the second law of thermodynamics is confirmed in the entangled system. It is
found that there is a same efficiency for both antiferromagnetic and
ferromagnetic cases, and the efficiency can be controlled in two manners: 1.
only by spin-spin interaction J and DM interaction D; 2. only by the
temperature T and concurrence C. In order to obtain a positive net work, we
need not entangle all qubits in two two-spin systems and we only require the
entanglement between qubits in a two-spin system not be zero. As the ratio of
entanglement between qubits in two two-spin systems increases, the efficiency
will approach infinitely the classical Carnot one. An interesting phenomenon is
an abrupt transition of the efficiency when the entanglements between qubits in
two two-spin systems are equal
The effect of Mediterranean diet on inflammatory biomarkers and components of metabolic syndrome in adolescent girls
Socioeconomic and Emotional Predictors of Decision Making for Timing Motherhood in Iranian Women in 2013
Thermal entanglement in the anisotropic Heisenberg model with Dzyaloshinskii-Moriya interaction in an inhomogeneous magnetic field
The thermal entanglement of a two-qubit anisotropic Heisenberg XXZ chain with Dzyaloshinskii-Moriya (DM) interaction in an inhomogeneous magnetic field was studied in detail. The effects of the DM parameter, external magnetic field (B), a parameter b which controls the inhomogeneity of B and the bilinear interaction parameters J(x) = J(y) not equal J(z) (the anisotropic case) on the concurrence (C) was formulated and studied in detail. The behaviors of the concurrences for the cases between (J = J(z) = 1) and (J = -1,J(z) = 1) and, (J = J(z) = -1) and (J = 1,J(z) = -1) at the ground state and at the thermal equilibrium are exactly the same. It was found that for the antiferromagnetic (AFM) case the entanglements persist to higher temperatures in comparison with the ferromagnetic (FM) case. In addition, the AFM case presents a special point at which the nonzero concurrences are all equal at some special temperatures. The further properties will be given in the text