ZERO FIELD ENTANGLEMENT IN DIPOLAR COUPLING SPIN SYSTEM AT NEGATIVE TEMPERATURE

2013 ◽  
Vol 11 (05) ◽  
pp. 1350050 ◽  
Author(s):  
GREGORY B. FURMAN ◽  
VICTOR M. MEEROVICH ◽  
VLADIMIR L. SOKOLOVSKY

A dipolar coupled spin system can achieve internal thermodynamic equilibrium states at negative absolute temperature. We study analytically and numerically the temperature dependence of the concurrence in a dipolar coupled spin-1/2 system in both nonzero and zero fields and show that, at negative temperatures, entangled states can exist even in zero magnetic field.

2019 ◽  
Vol 17 (03) ◽  
pp. 1950023
Author(s):  
Gregory B. Furman ◽  
Shaul D. Goren ◽  
Victor M. Meerovich ◽  
Vladimir L. Sokolovsky

In this paper, we study behavior of the correlations, both quantum and classical, under adiabatic demagnetization process in systems of nuclear spins with dipole–dipole interactions in an external magnetic field and in the temperature range including positive and negative temperatures. For a two-spin system, analytical expressions for the quantum and classical correlations are obtained. It is revealed that the field dependences of the quantum and classical correlations at positive and negative temperatures are substantially different. This difference most clearly appears in the case of zero magnetic field: at negative temperature, the measures of quantum correlations tend to the maximum values with a temperature increase. At positive temperature, these quantities tend to zero at a decrease of magnetic field. It is also found that, for the nearest-neighboring spins in the same field, the values of concurrence and discord are larger at negative temperatures than at positive ones.


2015 ◽  
Vol 233-234 ◽  
pp. 741-744
Author(s):  
Sergey Mikhailovich Podgornykh

Effect of the magnetic prehistory on the temperature dependence of the heat capacity of the superconducting Pb, La, Sn. has been studied. As soon as the external magnetic field riches the valueHext=HCthe superconductivity is completely destroyed. The trapped flux was produced in the ring specimen after the magnetic field was turned off atT<TC. We observed a difference of the value of the heat capacity between zero field cooled (ZFC) and field cooled (FC) states in zero magnetic field for the ring specimen. It is found that the FC heat capacity is smaller than the heat capacity both in the normal and in superconducting states.


2013 ◽  
Vol 11 (06) ◽  
pp. 1392001
Author(s):  
GREGORY B. FURMAN ◽  
VICTOR M. MEEROVICH ◽  
VLADIMIR L. SOKOLOVSKY

2013 ◽  
Vol 138 (18) ◽  
pp. 184202 ◽  
Author(s):  
Mark C. Butler ◽  
Micah P. Ledbetter ◽  
Thomas Theis ◽  
John W. Blanchard ◽  
Dmitry Budker ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
A. S. Kazakov ◽  
A. V. Galeeva ◽  
A. I. Artamkin ◽  
A. V. Ikonnikov ◽  
L. I. Ryabova ◽  
...  

AbstractWe report on observation of strong non-local photoconducitivity induced by terahertz laser pulses in non-zero magnetic field in heterostructures based on Hg1−xCdxTe films being in the topological phase. While the zero-field non-local photoconductivity is negligible, it is strongly enhanced in magnetic fields ~ 0.05 T resulting in appearance of an edge photocurrent that exceeds the respective dark signal by orders of magnitude. This photocurrent is chiral, and the chirality changes every time the magnetic field or the electric bias is reversed. Appearance of the non-local terahertz photoconductivity is attributed to features of the interface between the topological film and the trivial buffer.


1992 ◽  
Vol 06 (14) ◽  
pp. 879-889
Author(s):  
K. SUGAWARA ◽  
S. TANAKA

ESR of DPPH coated on Bi - Sr - Ca - Cu - O films fabricated on MgO (100) substrates by MOCVD have been studied for samples with different thicknesses, 1000 Å and 100 Å. Temperature dependence of the ESR peak-to-peak linewidth, ΔH pp , revealed that ΔH pp , increases with film thickness. The excess ESR linewidth, δ (ΔH pp ) was also analyzed in terms of (1-t)α, with t=T/T c , giving for example α=4±1 for the 1000 Å thick sample. The ESR lineshapes were distorted by rotating the samples in applied magnetic fields. Severe distortion was found for the 1000 Å sample below about 30 K, but the distortion almost disappears at temperatures above 30 K. The applied magnetic field effects were also examined in both field-cooled and zero-field-cooled cases.


1975 ◽  
Vol 30 (3) ◽  
pp. 361-371 ◽  
Author(s):  
H. Schuch ◽  
C. B. Harris

The spin locking method known from NMR is shown to be useful also in ESR for investigating spin lattice relaxation problems and “slow” motions, e. g. questions of energy transfer by triplet states in organic molecular crystals, and probing of nuclear quadrupolar splittings even smaller than the ESR line width at zero magnetic field.Optically detected ESR spin locking experiments for isolated triplet states in zero field are demonstrated. It is shown how the complication of incoming and decaying triplet states and relaxation between all three triplet sublevels has to be handled during spin locking. An application, the study of the cross-relaxation between electronic triplet spin states and deuteron or proton spins is presented. These experiments are possible in spite of the first order quenching of the hyperfine coupling in zero magnetic field. Another application is briefly mentioned, in which the adiabatically demagnetized state in the rotating frame is used to probe the electronic triplet state transfer and nuclear spin lattice relaxation.


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