Chain In Magnetic Field Research Articles

Spin nematic liquid of the S = 1/2 distorted diamond spin chain in magnetic field

The magnetization process of the S = 1/2 distorted diamond spin chain with anisotropic ferromagnetic interaction is investigated using numerical diagonalization of finite-size clusters. It is found that the spin nematic and SDW Tomonaga-Luttinger liquids can appear for sufficiently large easy axis anisotropy.

Detection of energy levels of a spin system on a quantum computer by probe spin evolution

We propose a method for detection of energy levels of arbitrary spin system on a quantum computer based on studies of evolution of only one probe spin. On the basis of the proposed method energy levels of spin systems are found on IBM’s quantum computer ibmq-bogota, among them are spin chain in magnetic field, triangle spin cluster, Ising model on squared lattice, a spin in magnetic field. The results of quantum calculations are in agreement with the theoretical ones. The method is efficient for estimation of the energy levels of many-spin systems and opens a possibility to achieve quantum supremacy in solving eigenvalue problem with development of multi-qubit quantum computers.

Study of Thermal Conductivity due to Spins in One-Dimensional Spin Systems AFeX<sub>3</sub> (A=Rb, Cs; X=Cl, Br)

Large contributions of the thermal conductivity due to spins, κspin, in low-dimensional spin systems are expected to be utilized as highly thermal conducting materials. One-dimensional spin system RbFeCl3 with ferromagnetic chains and CsFeBr3 with antiferromagnetic chains in magnetic fields have been prepared in order to observe the contribution of κspin to the value of thermal conductivity. The temperature dependence of the thermal conductivity parallel to spin chains along the c-axis, κ//c, of RbFeCl3 enhanced around 3 K and 10 K by the application of magnetic field. In the thermal conductivity perpendicular to c-axis, κ⊥c, of RbFeCl3, on the other hand, it has been found that only one peak around 3 K is enhanced by the application of magnetic field. Since κ⊥c is mainly owing to the thermal conductivity due to phonons, κphonon, it has been concluded the peak of κ//c around 10 K in magnetic fields is due to the contribution of κspin. For CsFeBr3, it has been found that κ//c shows two peaks around 3 K and 25 K while κ⊥c shows one peak around 12 K in zero field. This indicates that there is a marked contribution of κspin to κ//c. κ⊥ However, the details of the marked contribution of κspin to κ//c are not yet clear, since κ//c has been suppressed by the application of magnetic field in contrast with the enhancement of the thermal conductivity in RbFeCl3.

Low-temperature thermodynamics of the classical frustrated ferromagnetic chain in a magnetic field

Low-temperature magnetization curves of the classical frustrated ferromagnetic chain in the external magnetic field near the transition point between the ferromagnetic and the helical phases is studied. It is shown that the calculation of the partition function in the scaling limit reduces to the solution of the Schr\"{o}dinger equation of the special form for the quantum particle. It is proposed that the magnetization of the classical model in the ferromagnetic part of the phase diagram including the transition point defines the universal scaling function which is valid for quantum model as well. Explicit analytical formulae for the magnetization are given in the limiting cases of low and high magnetic fields. The influence of the easy-axis anisotropy on the magnetic properties of the model is studied. It is shown that even small anisotropy essentially changes the behavior of the susceptibility in the vicinity of the transition point.

Spin chains in magnetic field, non-skew-symmetric classical r-matrices and BCS-type integrable systems

We construct generalized Gaudin systems in an external magnetic field corresponding to arbitrary so ( 3 ) -valued non-skew-symmetric r-matrices with spectral parameters and non-homogeneous external magnetic fields. In the case of r-matrices diagonal in the sl ( 2 ) basis we calculate the spectrum and the eigen-values of the corresponding generalized Gaudin hamiltonians using the algebraic Bethe ansatz. We explicitly consider several one-parametric families of non-skew-symmetric classical r-matrices and the corresponding generalized Gaudin systems in a magnetic field. We apply these results to fermionic systems and obtain a wide class of new integrable fermionic BCS-type hamiltonians.

Entangled rings, matrix product states, and exact solutions ofXYZspin chains

Using the matrix product formalism, we introduce a two parameter family of exactly solvable $xyz$ spin 1/2 Heisenberg chains in magnetic field (with nearest neighbor interactions) and calculate the ground state and correlation functions in compact form. The ground state has a very interesting property: all the pairs of spins are equally entangled with each other. Therefore it is possible to engineer long-range entanglement in experimentally realizable spin systems on the one hand and study more closely quantum phase transition in such systems on the other.

Fisher–Hartwig conjecture and the correlators in XY spin chain

We apply the theorems from the theory of Toeplitz determinants to calculate the asymptotics of the correlators in the XY spin chain in the transverse magnetic field. The asymptotics of the correlators for the XX spin chain in the magnetic field are obtained.

NMR relaxation of quantum spin chains in magnetic fields

We investigate NMR relaxation rates 1/T_1 of quantum spin chains in magnetic fields. Universal properties for the divergence behavior of 1/T_1 are obtained in the Tomonaga-Luttinger-liquid state. The results are discussed in comparison with experimental results.

NMR relaxation rates of quantum spin chains in magnetic fields

We investigate NMR relaxation rates 1 / T 1 of gapped quantum spin chains in magnetic fields. Universal properties for the divergence behavior of 1 / T 1 with decreasing temperature are studied in a viewpoint of the Tomonaga–Luttinger liquid. On the basis of the results, 1 / T 1 for some typical gapped spin chains in the magnetic field is discussed in connection with experiments.

Thermodynamic properties of mixed-spin chains in magnetic field by the transfer matrix method

Motivated by recent experimental synthesis of molecule-based ferrimagnetics, we have investigated the thermodynamic properties of one-dimensional antiferromagnetic–ferromagnetic mixed spin- 1 2 lozenge chain in external magnetic fields at low temperature, using the transfer matrix method. The magnetization and the specific heat of the spin system have been evaluated numerically from the free energy. The magnetization as a function of the magnetic field at low temperature shows step-like plateau characterized by three critical magnetic fields, which reflects the competing effect of magnetic interactions and thermal fluctuations. The double-peak structure in the curves of the specific heat is also found, which comes from the huge variation of the long-range order parameters. Our results show that the thermodynamic properties of the mixed spin- 1 2 molecule-based ferrimagnetics are very analogous to the behaviors of the spin-1 and spin- 1 2 mixed antiferromagentic chain.

Resonance Frequency and Stiffness of Magnetic Bead Chain in Magnetic Field

Resonance Frequency and Stiffness of Magnetic Bead Chain in Magnetic Field

Gapless line for the anisotropic Heisenbergspin−12chain in a magnetic field and the quantum axial next-nearest-neighbor Ising chain

We study the anisotropic Heisenberg (XYZ) spin-1/2 chain placed in a magnetic field pointing along the x-axis. We use bosonization and a renormalization group analysis to show that the model has a non-trivial fixed point at a certain value of the XY anisotropy a and the magnetic field h. Hence, there is a line of critical points in the (a,h) plane on which the system is gapless, even though the Hamiltonian has no continuous symmetry. The quantum critical line corresponds to a spin-flop transition; it separates two gapped phases in one of which the Z_2 symmetry of the Hamiltonian is broken. Our study has a bearing on one of the transitions of the axial next-nearest neighbor Ising (ANNNI) chain in a transverse magnetic field. We also discuss the properties of the model when the magnetic field is increased further, in particular, the disorder line on which the ground state is a direct product of single spin states.

Statics of Magnetic Bead Chain in Magnetic Field

Experimental, numerical, and theoretical investigations have been carried out on statics of a magnetic bead chain in the magnetic field. Chains formed on a solenoid coil were observed and chain lengths and slant angles were measured by a digital microscope. It was deduced that (1) the chain length depends on both the surface loading of magnetic particles and the magnetic flux density, and is almost independent of the particle diameter if the sufficient amount of particles are provided; (2) chains incline in the inclined magnetic field and the inclination of the chain is enlarged by the gravitational force. These configurations of chains are approximately determined to minimize the total potential energy that consisted of the gravitational and magnetic potential energy. These characteristics were qualitatively confirmed by the numerical calculation with the two-dimensional Distinct Element Method. The investigation is expected to be utilized for the improvement of the two-component magnetic brush development system in electrophotography.

Dynamics of Magnetic Bead Chain in Magnetic Field.

Experimental and numerical investigations have been carried out on dynamics of magnetic bead chain in magnetic field. By the observation of vibration of chains formed on a solenoid coil, resonant frequency of the chains and equivalent stiffness were estimated. It was deduced that the resonant frequency was irrelevant to magnetic field, while the equivalent stiffness depended on magnetic field. From the numerical study using Distinct Element Method, it was also shown that the equivalent stiffness increased with the increase in magnetic field and decreased with the increase in chain length. Experimentally observed dependency of stiffness on magnetic field was explained as the combined effect of both magnetic field and chain length.

Statics of Magnetic Bead Chain in Magnetic Field.

Experimental, numerical, and theoretical investigations have been carried out on statics of magnetic bead chain in magnetic field. Chains formed on a solenoid coil were observed and chain lengths and slant angles were measured. It was clarified that the chain length depends on both the density of magnetic particles and the magnetic flux density. It was also clarified that chains have inclinations in the inclined magnetic field and that the inclination of a chain is enlarged by the gravitational force. These configurations of chains are determined to minimize the total potential energy that consists of the gravitational and magnetic potential energy. These characteristics were also confirmed by the numerical calculation with the Distinct Element Method.

Resonance Frequency and Stiffness of Magnetic Bead Chain in Magnetic Field

Resonance Frequency and Stiffness of Magnetic Bead Chain in Magnetic Field

Statics of Magnetic Bead Chain in Magnetic Field

Experimental, numerical, and theoretical investigations have been carried out on statics of a magnetic bead chain in the magnetic filed. Chains formed on a solenoid coil were observed and chain lengths and slant angles were measured by a digital microscope. It was deduced that (1) the chain length depends on both the weight of magnetic particles and the magnetic flux density; (2) chains have inclinations in the inclined magnetic field and that inclinations of the chains are enlarged by the gravitational force. These static configurations of chains are approximately determined to minimize the total potential energy that consisted of the gravitational and magnetic potential energy. These characteristics were qualitatively confirmed by the numerical calculation with the two-dimensional Distinct Element Method. The investigation is expected to be utilized for the improvement of the two-component magnetic brush development system in electrophotography.

Dynamics of Magnetic Bead Chain in Magnetic Field

Dynamics of Magnetic Bead Chain in Magnetic Field

Magnetic phases of CsCuCl3: Anomalous critical behavior.

We report high-resolution measurements of the specific heat of the hexagonal antiferromagnet ${\mathrm{CsCuCl}}_{3}$ with ferromagnetically coupled ${\mathrm{Cu}}^{2+}$ chains in magnetic fields parallel to the hexagonal axis. The zero-field data can be described assuming a second-order phase transition with a chiral XY critical exponent \ensuremath{\alpha} near 0.35, except very close to the N\'eel temperature where the transition seems to be of weakly first order. This might be an indication for the failure of XY chiral universality. The previously observed first-order transition from an ``umbrella'' to a coplanar spin structure at high fields merges the transition line to the paramagnet in a multicritical point (${\mathit{T}}_{\mathit{c}}$=10.59 K, ${\mathit{B}}_{\mathit{m}}$=5.5 T). The transition to the new coplanar structure from the saturated paramagnetic phase above ${\mathit{B}}_{\mathit{m}}$ seems, rather unexpectedly, also to be describable as a second-order transition with \ensuremath{\alpha}\ensuremath{\approxeq}0.23. \textcopyright{} 1996 The American Physical Society.

Multichannel density-functional calculations for atoms and atomic chains in magnetic fields of compact stars.

Ground-state energies of atoms and atomic chains in strong to superstrong magnetic fields (B\ensuremath{\approxeq}2.4\ifmmode\times\else\texttimes\fi{}${10}^{6}$ \char21{} 8.5\ifmmode\times\else\texttimes\fi{}${10}^{8}$ T) are calculated within the single-particle scheme of a heuristic density-functional method. From these we find condensation energies and binding lengths. Using the local Dirac exchange functional, the corresponding equations are solved iteratively, expanding the wave functions with respect to Landau functions in the transverse directions and directly integrating along the longitudinal direction. Dropping the adiabatic approximation, we extrapolate our results with respect to the number of Landau channels taken into account. The values found by this extrapolation correspond to calculations without any restriction on the allowed wave functions. \textcopyright{} 1996 The American Physical Society.