ENTANGLEMENT MODULATION IN A SPIN CHAIN BY A LOCAL IMPURITY

2008 ◽  
Vol 06 (supp01) ◽  
pp. 567-573 ◽  
Author(s):  
TONY J. G. APOLLARO ◽  
ALESSANDRO CUCCOLI ◽  
ANDREA FUBINI ◽  
FRANCESCO PLASTINA ◽  
PAOLA VERRUCCHI

We study the ground-state entanglement properties of an XX spin 1/2 chain in transverse field, in its quasi-long-ranged ordered phase, with a magnetic impurity, represented in terms of an additional transverse magnetic field located at one precise site. For such a system, we show that a control of the ground state entanglement can be achieved by acting on the impurity field. To demonstrate this possibility, we evaluate exactly the nearest neighbor and next-nearest neighbor concurrence in the presence of the impurity. It turns out that either an enhancement or a quenching of entanglement between selected spin pairs can be obtained by acting on the intensity of the impurity. For specific values of the magnetic field a spatial modulation of concurrence along the chain is also obtained.

1998 ◽  
Vol 76 (7) ◽  
pp. 507-513
Author(s):  
O Bolina ◽  
J R Parreira

We show that the ground state of the xy model (ferromagnetic orantiferromagnetic) in a transverse magnetic field h --- for any spin value, in any dimension --- is the state with all spins aligned antiparallel to the field when h is greater than some critical value hc. In particular, for the spin-1/2 linear chain, we study the behavior of correlations as functions of the magnetic field. PACS Nos.: 75.10Jm and 64.60.Cm


Experiments on the penetration of a magnetic field (de Haas and Casimir-Jonker 1934) into superconductors have shown that, when a superconducting cylinder is placed in an increasing transverse field, penetration of the field first occurs when the applied field strength reaches a value 0·50 H k , where H k is the critical field corresponding to the temperature of the experiment. Since, for this value of the applied field, the field strength, at the surface of the cylinder (von Laue 1932) where it is intersected by a diametral plane perpendicular to the direction of the field, will be precisely H k , the above result is in accordance with expectation. On the other hand, it was found by de Haas, Voogd and Jonker (1934) that under the same conditions the cylinder first exhibited electrical resistance when the applied field strength reached the value 0·58 H k . Since this discrepancy probably results from the properties of the “intermediate state” (Peierls 1936; London 1936; Landau 1937) occurring when the magnetic field just begins to penetrate the superconductor, it seemed desirable to investigate the matter in more detail.


2012 ◽  
Vol 27 (01n03) ◽  
pp. 1345033 ◽  
Author(s):  
N. CANOSA ◽  
L. CILIBERTI ◽  
R. ROSSIGNOLI

We examine the quantum correlations of spin pairs in the ground state of finite XY chains in a transverse field, by evaluating the quantum discord as well as other related entropic measures of quantum correlations. A brief review of the latter, based on generalized entropic forms, is also included. It is shown that parity effects are of crucial importance for describing the behavior of these measures below the critical field. It is also shown that these measures reach full range in the immediate vicinity of the factorizing field, where they become independent of separation and coupling range. Analytical and numerical results for the quantum discord, the geometric discord and other measures in spin chains with nearest neighbor coupling and in fully connected spin arrays are also provided.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Evgeny D. Filippov ◽  
Sergey S. Makarov ◽  
Konstantin F. Burdonov ◽  
Weipeng Yao ◽  
Guilhem Revet ◽  
...  

AbstractWe analyze, using experiments and 3D MHD numerical simulations, the dynamic and radiative properties of a plasma ablated by a laser (1 ns, 10$$^{12}$$ 12 –10$$^{13}$$ 13 W/cm$$^2$$ 2 ) from a solid target as it expands into a homogeneous, strong magnetic field (up to 30 T) that is transverse to its main expansion axis. We find that as early as 2 ns after the start of the expansion, the plasma becomes constrained by the magnetic field. As the magnetic field strength is increased, more plasma is confined close to the target and is heated by magnetic compression. We also observe that after $$\sim 8$$ ∼ 8  ns, the plasma is being overall shaped in a slab, with the plasma being compressed perpendicularly to the magnetic field, and being extended along the magnetic field direction. This dense slab rapidly expands into vacuum; however, it contains only $$\sim 2\%$$ ∼ 2 % of the total plasma. As a result of the higher density and increased heating of the plasma confined against the laser-irradiated solid target, there is a net enhancement of the total X-ray emissivity induced by the magnetization.


2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Rita Choudhury ◽  
Utpal Jyoti Das

The combined effect of a transverse magnetic field and radiative heat transfer on unsteady flow of a conducting optically thin viscoelastic fluid through a channel filled with saturated porous medium and nonuniform walls temperature has been discussed. It is assumed that the fluid has small electrical conductivity and the electromagnetic force produced is very small. Closed-form analytical solutions are constructed for the problem. The effects of the radiation and the magnetic field parameters on velocity profile and shear stress for different values of the viscoelastic parameter with the combination of the other flow parameters are illustrated graphically, and physical aspects of the problem are discussed.


2020 ◽  
Vol 90 (3) ◽  
pp. 482
Author(s):  
Н.М. Горшунов ◽  
Е.П. Потанин

Equations are obtained that describe the characteristics of the azimuthal motion and radial expansion of a plasma jet under the action of a rotating transverse magnetic field of a dipole configuration in a longitudinal static magnetic field. The analysis was carried out both in the multicomponent approximation and on the basis of MHD equations taking into account the Hall effect. Based on the obtained dependences of the azimuthal and radial ion velocities on the magnetic field values, the separation characteristics of the direct-flow plasma centrifuge are estimated for the separation of a two-component binary mixture simulating spent nuclear fuel. It was shown that the concentration of the heavy uranium-plutonium component in the product flow can be increased from the initial 96 to 99.8% with a fuel component extraction of 0.87.


2018 ◽  
Vol 16 (6) ◽  
pp. 385-390
Author(s):  
Shikha BINWAL ◽  
Jay K JOSHI ◽  
Shantanu Kumar KARKARI ◽  
Predhiman Krishan KAW ◽  
Lekha NAIR ◽  
...  

A floating emissive probe has been used to obtain the spatial electron temperature (Te) profile in a 13.56 MHz parallel plate capacitive coupled plasma. The effect of an external transverse magnetic field and pressure on the electron temperature profile has been discussed. In the un-magnetised case, the bulk region of the plasma has a uniform Te. Upon application of the magnetic field, the Te profile becomes non-uniform and skewed.  With increase in pressure, there is an overall reduction in electron temperature. The regions adjacent to the electrodes witnessed a higher temperature than the bulk for both cases. The emissive probe results have also been compared with particle-in-cell simulation results for the un-magnetised case.


2019 ◽  
Vol 64 (9) ◽  
pp. 787
Author(s):  
S. N. Afanasyev

The method of diffusion chamber in the magnetic field making use of a bremsstrahlung beam with a maximum photon energy of 150 MeV is applied to study the 12C(y,3a) and 16O(y,4a) reactions. A resonance identified as the ground state of 8Be nucleus is found in the distribution of events over the energy of the relative motion of two a-particles. The partial cross-sections of the 8Be nucleus formation channels are measured. It is shown that the mechanism of interaction between a y-quantum and a virtual a-particle pair takes place in this case.


Author(s):  
И.А. Беляев ◽  
Д.А. Бирюков ◽  
А.В. Котляр ◽  
Е.А. Белавина ◽  
П.А. Сардов ◽  
...  

The results of an experimental study of the salt melt downflow in a uniformly heated pipe under the influence of a strong transverse magnetic field are presented. The changes of heat transfer coefficients and statistical characteristics of temperature fluctuations under the influence of the magnetic field are investigated. The peculiarities of the transition of the viscous-gravitational flow in the viscous-inertial-gravitational flow at Reynolds numbers (Re=3000-5000) under the influence of the magnetic field (Ha=17) were studied.


1995 ◽  
Vol 09 (24) ◽  
pp. 3229-3240 ◽  
Author(s):  
G. CRISTOFANO ◽  
D. GIULIANO ◽  
G. MAIELLA ◽  
L. VALENTE

The effect of dissipation on the electron ground state wave function on a torus in the presence of an external transverse magnetic field is analyzed on large time scales [Formula: see text]. Its extension to the multiparticle center of the mass wave function is also given. The novel transport properties of the system are then studied by applying Laughlin gauge argument with the use of the magnetic translation operators.


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