- Generalized spin-wave theory: Application to the... - OUP Academic.
- 27 - Elementary excitations: the Bogoliubov-Valatin transformation.
- Faddeev–Popov ghost - Wikipedia.
- PDF Antiferromagnetic Spin Chains - Department of Physics.
- PDF Physics 211b Condensed Matter Physics Hw Assignment #5.
- Introduction to gauge theory - Wikipedia.
- PDF Bogoliubov Transformations and Quantum Decoherence in An Atomic Bose.
- Linear spin wave theory for the frustrated... - ScienceDirect.
- PDF Mathematical Analysis of the BCS-Bogoliubov Theory 1 Introduction.
- Bogoliubov transformation 3-mode | Physics Forums.
- Physical Review B - Volume 105 Issue 17.
- Bogoliubov transformation - Detailed Pedia.
- Spin waves I - Book chapter - IOPscience.
- Holstein-Primakoff and Bogoliubov transformation - 知乎.
Generalized spin-wave theory: Application to the... - OUP Academic.
Journal information. 1968-1988 Journal of Physics C: Solid State Physics doi: 10.1088/issn.0022-3719 Online ISSN: 0022-3719 Print ISSN: 0022-3719; Journal history. 1989-present Journal of Physics: Condensed Matter. One is that the bosonic Hamiltonian is diagonalized analytically by Bogoliubov transformation [27], the other is that the relation between pitch angle and the frustration parameter is derived as a result of our analyses on the spin wave spectrum, while the previous works took it as a premise got from the classical treatment. 2.
27 - Elementary excitations: the Bogoliubov-Valatin transformation.
Magnetic order exists as a ground state property only, below some critical temperature at which a phase transition takes place. It can be described using the molecular or mean field approximation. For spin excitations at the surface of magnetic solids ( surface magnons) we refer to [179, 180]. Keywords Spin Wave Elementary Excitation.
Faddeev–Popov ghost - Wikipedia.
Where γ k = 1 / z ∑ δ e i k ⋅ δ. And z is number of NN and δ is location of NN. to diagonalize apply Bogoliubov transformation α k = u k a k − v k b − k +; β k + = − v k a k + u k b − k + this gives us the following results H 1 = ∑ k ϵ k ( α k + α k + β k + β k) where ϵ k = z J S ∑ k 1 − γ k 2 My question: Till 2nd step, I know what's going on.
PDF Antiferromagnetic Spin Chains - Department of Physics.
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 line in these materials in the presence of dc electric fields.
PDF Physics 211b Condensed Matter Physics Hw Assignment #5.
Conventional spin wave expansion transformations -Holstein-Primakoff -Fourier transformation using reduced BZ -diagonalization: Bogoliubov transformation H^ = 1 2 X ij JijSi¢SjJij=J>0 H = Ecl+H2+H4+O(b6) Ecl= ¡DNJS2 H2= S X ij Jij ³ by ibi+b y jbj+bibj+b y ib y j ´ bi= r 2 N X k eik¢riA kbi= r 2 N X k eik¢riB k µ Ak By ¡k ¶ = µ ukvk ¡vkuk ¶µ ®k. In the zero external field limit and for a spin 1/2 lattice the bound M(β) is implicitly given by the equation 1 - M = 2M(2π)"M j dnp(eβE^IM-ί)'1, (1) where β is the inverse temperature and E p stands for the energy of a spin wave with momentum p. The integration is carried over the first Brillouin zone. By inspection,.
Introduction to gauge theory - Wikipedia.
After a transformation of the diffusion problem onto the fixed domain, we use the formal method of two-scale asymptotic expansion to derive the upscaled model, which is nonlinearly coupled through effective coefficients. The effective model is implemented and validated using an application-inspired model problem. Goldstone modes, and spin-wave theory. Using the Neel state as the broken symmetry state one might think we should be able to find spin-wave excitations which we know are gapless, and lead to power law correlations.... Bogoliubov transformation The Bogoliubov transformation, ck = ukak −vkb.
PDF Bogoliubov Transformations and Quantum Decoherence in An Atomic Bose.
Diagonalization: Bogoliubov transform (see BCS theory) c k =u k k +v k !k d k =u k k +v k !k +and: !,! "#$=!","+#=1 New bosonic operators with u k, v kreal Conditions on u kv k [!,"]=0 (2) Eliminate cross terms like (αβ) to diagonalize H: u k v k k v k 2 Ex: terms in ! k !k !k ku k v+!u 2 2u k v k k (u k 2+v k 2)=0.
Linear spin wave theory for the frustrated... - ScienceDirect.
The connection between quadratic Hamiltonians, Bogoliubov transformations, and symplectic transformations is discussed in the Fock representation, and their relevance for squeezing operations in quantum optics is pointed out. The results for this rather general class of transformations are proved in a self‐contained fashion.
PDF Mathematical Analysis of the BCS-Bogoliubov Theory 1 Introduction.
Adding to (27.3) the energy ξ k of one (unbound) electron then yields the quasiparticle excitation energy, where we used Eqs. (26.24) and (26.27). Thus the energy needed to add an electron in state k ↓ is σ k. If we calculate the energy required to remove an electron in a state - k ↓ we also obtain σ k. Note the minimum excitation. Where a, b an c are boson operators. As there are "non-diagonal" terms, the idea is use Bogoliubov Transformation for make the hamiltonian a diagonal hamiltonian.... But for 2 differents bosons, the tranformation is: alpha_ {k} = cosh (theta_ {k}) a_ {k} - sinh (theta_ {k}) b*_ {k}, where b* is b-dagger.
Bogoliubov transformation 3-mode | Physics Forums.
We discuss the Bogoliubov transformation of the scalar wave functions caused by the change of coordinates in four-dimensional de Sitter space. It is shown that the exact Bogoliubov coefficients can. In 2005, a generalization to insulators preserving time-reversal symmetry and exhibiting strong spin–orbit interactions was discovered by Kane and Mele, known as the quantum spin-Hall (QSH) phase. 31 31. C. L. Kane and E. J. Mele, “ Z 2 topological order and the quantum spin Hall effect,” Phys. Rev. Lett. 95, 146802 (2005). 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.
Physical Review B - Volume 105 Issue 17.
Bogoliubov transformation. This theory is called the Bogoliubov theory. The ground state of the BCS Hamiltonian is discussed by several authors. In 1961 Mattis and Lieb [5] studied the wavefunction of the ground state of the BCS Hamiltonian... wave vector k ∈ Λ and on spin.
Bogoliubov transformation - Detailed Pedia.
Journal of Physics B: Atomic, Molecular and Optical Physics covers the study of atoms, ions, molecules and clusters, and their structure and interactions with particles, photons or fields. The Bogoliubov transformation is the canonical transformation mapping the... annihilate and create quasiparticles (each with well-defined energy, momentum and spin but in a quantum superposition of electron and hole state), and have coefficients and given by eigenvectors... BCS wave function is an example of squeezed coherent state of.
Spin waves I - Book chapter - IOPscience.
The zero-temperature flow equations derived from the extension of the Bogoliubov transformation to order for the ground-state energy, the spin-wave velocity, and the staggered magnetization are solved exactly and yield results which are in agreement with those obtained by a perturbative treatment of the magnon interactions. Holstein-Primakoff transformation was developed in 1940 by Theodore Holstein, a graduate student at the time and Henry Primakoff. The HP transformation maps the spin opreators into Bosonic annihilation and creation operators, which diagonalizes the Hamiltonian in the corresponding k space for FM under linear excitation regime (low temperature). Spin–statistics relation violated. The Faddeev–Popov ghosts violate the spin–statistics relation, which is another reason why they are often regarded as "non-physical" particles. For example, in Yang–Mills theories (such as quantum chromodynamics) the ghosts are complex scalar fields (spin 0), but they anti-commute (like fermions).
Holstein-Primakoff and Bogoliubov transformation - 知乎.
Light-induced thermal hysteresis and high-spin low-spin domain formation evidenced by optical microscopy in a spin-crossover single crystal Houcem Fourati, Mamadou Ndiaye, Mouhamadou Sy, Smail Triki, Guillaume Chastanet, Sébastien Pillet, and Kamel Boukheddaden Phys. Rev. B 105, 174436 (2022) – Published 31 May 2022 Show Abstract. PHYS598 A.J.Leggett Lecture 11 The Bogoliubov-de Gennes and Andreev Equations... 3 Let's first consider an even number of fermions at T= 0 and thus consider a single state of the system (which need however not necessarily be the ground state). As in lecture 5 we assume the general form of the wave function corresponds to the formation.
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