Spin Bogoliubov Transformation

17.07.2022

Linear spin wave theory for the frustrated ferromagnetic spin.
BEC of magnons and spin wave interactions in QAF.
BCS Theory: Bogoliubov Transformation for Fermions.
Bogoliubov quasiparticles in superconducting qubits - SciPost.
(PDF) On Spin-Statistics and Bogoliubov Transformations in.
Bogoliubov transformation 3-mode - Physics Forums.
Spin and field squeezing in a spin-orbit coupled Bose.
(PDF) A step-by-step Bogoliubov transformation method for.
Spin bogoliubov transformation.
CiteSeerX — Citation Query On a new method in the theory of.
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PDF Quantum Ising Models - Weebly.
PDF Quantum Phase Transitions in an Integrable One-Dimensional Spin Model.

Linear spin wave theory for the frustrated ferromagnetic spin.

We develop an exact generalized Bogoliubov transformation for the spin $3∕2$ Hubbard model with large anti-Hunds rule coupling near half filling. Since the transformation is unitary, we can employ standard approximate mean-field theory methods in the full Hilbert space to analyze the doped Mott insulator, in contrast to a conventional approach based on truncated Hilbert spaces complemented.

BEC of magnons and spin wave interactions in QAF.

Thermal equilibrium. Others rest on the specific structure of the model (spin system, simple cubic lattice, nearest neighbor coupling etc.) and have limited applicability. Our concern here will be with general estimates of the type used in [1-4]. One of these estimates will turn out to be an improved version of Bogoliubov's inequality. The Federbush, massless Thirring and continuum Ising models and related integrable relativistic quantum field theories are studied. It is shown that local and covariant classical field operators exist that generate Bogoliubov transformations of the annihilation and creation operators on the Fock spaces of the respective models.

BCS Theory: Bogoliubov Transformation for Fermions.

If such quantum melting takes place our linear spin wave approxima-tion is not valid anymore. The number of bosons in the groundstate will become large and the linearized form of the spinwave equation will not be justiﬁed. Actually the problem is even much worse: in the HP transformation we assumed that there is long-range antiferromagnetic. We theoretically investigate one-dimensional three-component spin-orbit-coupled Fermi gases in the presence of the Zeeman field. By solving the Bogoliubov-de Gennes equations, we obtain the phase diagram at a given chemical potential and order parameter. We show that, with increasing the intensity of the Zeeman field, in addition to undergoing a phase transition from Bardeen-Cooper-Schrieffer..

Bogoliubov quasiparticles in superconducting qubits - SciPost.

(PDF) On Spin-Statistics and Bogoliubov Transformations in.

(1) Show that the Bogoliubov transformations in Eqn. (12.55) of the lecture notes preserve the fermion anticommutation relations. (2) Show that the BCS ground state wavefunction |Gi in Eqn. (12.83) of the lecture notes is annihilated by the Bogoliubov annihilation operator γ kσ. (3) Show that X k,σ σc† kσ c kσ = X k,σ σγ† kσ γ kσ.

Bogoliubov transformation 3-mode - Physics Forums.

The generalized Bogoliubov transformation, Equation , for these parameters is The Green's function for the Dirac field in phase space is where is a time-like vector. Then, the physical energy-momentum tensor is In order to calculate the Stefan-Boltzmann law, taking leads to This is the Stefan-Boltzmann law for the Dirac field in phase space.

Spin and field squeezing in a spin-orbit coupled Bose.

On the bosonic Fock space, a family of Bogoliubov transformations corresponding to a strongly continuous one-parameter group of symplectic maps R(t) is considered. Under suitable assumptions on the generator A of this group, which guarantee that the induced representations of CCR are unitarily equivalent for all time t, it is known that the unitary operator U_{nat}(t) which implement this. Dec 01, 2021 · The Bogoliubov transformation is used to diagonalize the Hamiltonian analytically, that gives an expression of the spin wave spectrum ω k. From analyzing the behavior of the spectrum curve, we have found that relation between the pitch angle and the frustration parameter, i.e. φ = arccos ( 1 4 α ) can be derived as a result of our analyses.

(PDF) A step-by-step Bogoliubov transformation method for.

To diagonalize the Hamiltonian ( 2.33 ), we use the so-called Bogoliubov transformation in the form presented in textbooks. In chapter 4 , I will give a demonstration of this transformation for more general models. In this procedure, one introduces new creation and annihilation operators , , and write. The spin gives us information on the single-particle orbitals near the Fermi level.... We have found relationships among the particle-number parity, the Bogoliubov transformation, and the time-reversal symmetry of the Hartree-Fock-Bogoliubov Hamiltonian. Then we showed that the lowest-energy solution of the HFB equation has even particle.

Spin bogoliubov transformation.

A single real scalar field of spin zero obeying the Klein-Gordon equation in flat space-time under external conditions is considered in the context of the spin-statistics connection. An imposed accelerated boundary on the field is made to become, in the far future, (1) asymptotically inertial and (2) asymptotically non-inertial (with an infinite acceleration). The constant acceleration Unruh. Using bosonic spin deviation operators and an analysis of the quantum mechanical equations of motion we have numerically constructed the canonical Bogoliubov transformation and diagonalized the spin wave Hamiltonian for the interaction parameter set of Gd 2 Ti 2 O 7. We have obtained the spin wave dispersion spectrum for nearest neighbour. The Heisenberg spin- S quantum antiferromagnet is studied near the large-spin limit, applying a new continuous unitary transformation which extends the usual Bogoliubov transformation to higher order in the 1/ S -expansion of the Hamiltonian. This allows to diagonalize the bosonic Hamiltonian resulting from the Holstein-Primakoff representation beyond the conventional spin-wave approximation.

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Bogoliubov transformation as long as only quadratic terms in the creation from PHYSICS 560 at Oxford University.

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Sect. IV a generalized Bogoliubov theory taking into account Gold-stone modes is discussed and quantum phase operator is introduced. Finally, we summarize and conclude in Sect. V. 2 The Bogoliubov transformation A second quantized quantum mechanical theory of a weakly in-teracting Bose gas was developed by N. N. Bogoliubov and applied to the super. Spin-Charge Separation in Polyacetylene Stefanos Papanikolaou Department of Physics, University of Illinois at Urbana-Champaign, IL 61801 This essay describes the experimental observations that led to the formulation of the SSH soli-... Finally, H can be brought to a diagonal form by a Bogoliubov transformation: aks.

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TY - JOUR. T1 - Stark effects in rutile antiferromagnets. AU - Halley, J. Woods. PY - 1969. Y1 - 1969. N2 - We show that, as a consequence of the fact that the Bogoliubov transformation mixes spin waves on different sublattices, the phenomenological Loudon Hamiltonian describing the two spin-wave absorption in rutile antiferromagnets also predicts a linear Stark effect on the two spin-wave. Transformation: u σ(x) → v∗ σ (x) and E η →−E η. Therefore, every eigenstate with energy E has a partner at −E. These two states describe the same physical degrees of freedom, as the Bogoliubov quasiparticle operators associated with them satisfy E = † −E. This redundancy has been removed by multiplying a factor of 1/2 in the. Dec 30, 1988 · A step-by-step Bogoliubov transformation method for diagonalising a kind of non-Hermitian effective Hamiltonian... it asserts that particles that have half-integer spin (fermions) are described.

PDF Quantum Phase Transitions in an Integrable One-Dimensional Spin Model.

Jul 28, 2021 · 1 Answer. The transformation should be unitary. In other words, if we write. Note also that the transformation is that of a pair of states with different quantum numbers: k, ↑ and − k, ↓ - they have different spin and momentum, i.e. c − k, ↓ † is not the same as c k, ↑ † = u k d k, ↑ † + v k d − k, ↓, which the OP seems.