Log in

Relevant bibliographies by topics / Fermionic lattice models / Journal articles

To see the other types of publications on this topic, follow the link: Fermionic lattice models.

Journal articles on the topic 'Fermionic lattice models'

Author: Grafiati

Published: 4 May 2024

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 journal articles for your research on the topic 'Fermionic lattice models.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.

1

Zhao, J., C. A. Jiménez-Hoyos, G. E. Scuseria, D. Huerga, J. Dukelsky, S. M. A. Rombouts, and G. Ortiz. "Composite fermion-boson mapping for fermionic lattice models." Journal of Physics: Condensed Matter 26, no. 45 (October 16, 2014): 455601. http://dx.doi.org/10.1088/0953-8984/26/45/455601.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Matlak, M., B. Grabiec, and S. Krawiec. "Electronic Correlations within Fermionic Lattice Models." Acta Physica Polonica A 112, no. 3 (September 2007): 537–47. http://dx.doi.org/10.12693/aphyspola.112.537.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Bennett, Ed, Jack Holligan, Deog Ki Hong, Ho Hsiao, Jong-Wan Lee, C. J. David Lin, Biagio Lucini, Michele Mesiti, Maurizio Piai, and Davide Vadacchino. "Sp(2N) Lattice Gauge Theories and Extensions of the Standard Model of Particle Physics." Universe 9, no. 5 (May 17, 2023): 236. http://dx.doi.org/10.3390/universe9050236.

Full text

Abstract:

We review the current status of the long-term programme of numerical investigation of Sp(2N) gauge theories with and without fermionic matter content. We start by introducing the phenomenological as well as theoretical motivations for this research programme, which are related to composite Higgs models, models of partial top compositeness, dark matter models, and in general to the physics of strongly coupled theories and their approach to the large-N limit. We summarise the results of lattice studies conducted so far in the Sp(2N) Yang–Mills theories, measuring the string tension, the mass spectrum of glueballs and the topological susceptibility, and discuss their large-N extrapolation. We then focus our discussion on Sp(4), and summarise the numerical measurements of mass and decay constant of mesons in the theories with fermion matter in either the fundamental or the antisymmetric representation, first in the quenched approximation, and then with dynamical fermions. We finally discuss the case of dynamical fermions in mixed representations, and exotic composite fermion states such as the chimera baryons. We conclude by sketching the future stages of the programme. We also describe our approach to open access.

APA, Harvard, Vancouver, ISO, and other styles

4

FURUKAWA, NOBUO, SHIN MIYAHARA, and C. HOTTA. "FRUSTRATED METALS ON A TRIANGULAR LATTICE." International Journal of Modern Physics C 20, no. 09 (September 2009): 1477–84. http://dx.doi.org/10.1142/s0129183109014539.

Full text

Abstract:

Frustrated metals are investigated by numerical methods. In the absence of fermionic dynamics, the models are equivalent to a frustrated Ising model on a geometrically frustrated lattice, where macroscopic degeneracies are observed in the ground states. By taking into account fermionic hoppings, the models show partial loss of degeneracy, but still remains to be frustrated. Various properties of the system, including charge correlations, are also examined.

APA, Harvard, Vancouver, ISO, and other styles

5

Gaiotto, Davide, and Anton Kapustin. "Spin TQFTs and fermionic phases of matter." International Journal of Modern Physics A 31, no. 28n29 (October 19, 2016): 1645044. http://dx.doi.org/10.1142/s0217751x16450445.

Full text

Abstract:

We study lattice constructions of gapped fermionic phases of matter. We show that the construction of fermionic Symmetry Protected Topological orders by Gu and Wen has a hidden dependence on a discrete spin structure on the Euclidean space-time. The spin structure is needed to resolve ambiguities which are otherwise present. An identical ambiguity is shown to arise in the fermionic analog of the string-net construction of 2D topological orders. We argue that the need for a spin structure is a general feature of lattice models with local fermionic degrees of freedom and is a lattice analog of the spin-statistics relation.

APA, Harvard, Vancouver, ISO, and other styles

6

Itoh, K., M. Kato, H. Sawanaka, H. So, and N. Ukita. "Fermionic symmetry in Ichimatsu-decomposed lattice models." Nuclear Physics B - Proceedings Supplements 119 (May 2003): 903–5. http://dx.doi.org/10.1016/s0920-5632(03)80481-4.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

PESANDO, IGOR. "VECTOR INDUCED LATTICE GAUGE THEORIES." Modern Physics Letters A 08, no. 29 (September 21, 1993): 2793–801. http://dx.doi.org/10.1142/s0217732393003184.

Full text

Abstract:

We consider vector induced lattice gauge theories, in particular we consider the QED induced and we show that at negative temperature corresponds to the dimer problem while at positive temperature it describes a gas of branched polymers with loops. We show that the fermionic models have D c = 6 as upper critical dimension for N ≠ ∞ while the N = ∞ model has no upper critical dimension. We also show that the bosonic models without potential are not critical in the range of stability of the integral definition of the partition function but they behave as the fermionic models when we analytically continue the free energy.

APA, Harvard, Vancouver, ISO, and other styles

8

Sazonov, V. K. "Convergent perturbation theory for lattice models with fermions." International Journal of Modern Physics A 31, no. 13 (May 8, 2016): 1650072. http://dx.doi.org/10.1142/s0217751x1650072x.

Full text

Abstract:

The standard perturbation theory in QFT and lattice models leads to the asymptotic expansions. However, an appropriate regularization of the path or lattice integrals allows one to construct convergent series with an infinite radius of the convergence. In the earlier studies, this approach was applied to the purely bosonic systems. Here, using bosonization, we develop the convergent perturbation theory for a toy lattice model with interacting fermionic and bosonic fields.

APA, Harvard, Vancouver, ISO, and other styles

9

Giordano, Matteo, and Tamás Kovács. "Localization of Dirac Fermions in Finite-Temperature Gauge Theory." Universe 7, no. 6 (June 8, 2021): 194. http://dx.doi.org/10.3390/universe7060194.

Full text

Abstract:

It is by now well established that Dirac fermions coupled to non-Abelian gauge theories can undergo an Anderson-type localization transition. This transition affects eigenmodes in the lowest part of the Dirac spectrum, the ones most relevant to the low-energy physics of these models. Here we review several aspects of this phenomenon, mostly using the tools of lattice gauge theory. In particular, we discuss how the transition is related to the finite-temperature transitions leading to the deconfinement of fermions, as well as to the restoration of chiral symmetry that is spontaneously broken at low temperature. Other topics we touch upon are the universality of the transition, and its connection to topological excitations (instantons) of the gauge field and the associated fermionic zero modes. While the main focus is on Quantum Chromodynamics, we also discuss how the localization transition appears in other related models with different fermionic contents (including the quenched approximation), gauge groups, and in different space-time dimensions. Finally, we offer some speculations about the physical relevance of the localization transition in these models.

APA, Harvard, Vancouver, ISO, and other styles

10

Ul Haq, Rukhsan, and Louis H. Kauffman. "Z2 Topological Order and Topological Protection of Majorana Fermion Qubits." Condensed Matter 6, no. 1 (February 24, 2021): 11. http://dx.doi.org/10.3390/condmat6010011.

Full text

Abstract:

The Kitaev chain model exhibits topological order that manifests as topological degeneracy, Majorana edge modes and Z2 topological invariant of the bulk spectrum. This model can be obtained from a transverse field Ising model(TFIM) using the Jordan–Wigner transformation. TFIM has neither topological degeneracy nor any edge modes. Topological degeneracy associated with topological order is central to topological quantum computation. In this paper, we explore topological protection of the ground state manifold in the case of Majorana fermion models which exhibit Z2 topological order. We show that there are at least two different ways to understand this topological protection of Majorana fermion qubits: one way is based on fermionic mode operators and the other is based on anti-commuting symmetry operators. We also show how these two different ways are related to each other. We provide a very general approach to understanding the topological protection of Majorana fermion qubits in the case of lattice Hamiltonians. We then show how in topological phases in Majorana fermion models gives rise to new braid group representations. So, we give a unifying and broad perspective of topological phases in Majorana fermion models based on anti-commuting symmetry operators and braid group representations of Majorana fermions as anyons.

APA, Harvard, Vancouver, ISO, and other styles

11

Maraner, Paolo, and Jiannis K. Pachos. "Yang–Mills gauge theories from simple fermionic lattice models." Physics Letters A 373, no. 30 (July 2009): 2542–45. http://dx.doi.org/10.1016/j.physleta.2009.05.029.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Zverev, N. V., and A. A. Slavnov. "Nonlocal lattice fermionic models on a two-dimensional torus." Theoretical and Mathematical Physics 115, no. 1 (April 1998): 448–57. http://dx.doi.org/10.1007/bf02575503.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Vollhardt, Dieter. "High dimensions - a new approach to fermionic lattice models." Physica B: Condensed Matter 169, no. 1-4 (February 1991): 277–84. http://dx.doi.org/10.1016/0921-4526(91)90240-f.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Matlak, M., B. Grabiec, and S. Krawiec. "Fermionic lattice models and electronic correlations: Magnetism and superconductivity." Journal of Non-Crystalline Solids 354, no. 35-39 (October 2008): 4326–29. http://dx.doi.org/10.1016/j.jnoncrysol.2008.06.045.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Landa-Marbán, David, Wolfgang Bietenholz, and Ivan Hip. "Features of a 2d gauge theory with vanishing chiral condensate." International Journal of Modern Physics C 25, no. 10 (September 11, 2014): 1450051. http://dx.doi.org/10.1142/s012918311450051x.

Full text

Abstract:

The Schwinger model with Nf ≥ 2 flavors is a simple example for a fermionic model with zero chiral condensate Σ (in the chiral limit). We consider numerical data for two light flavors, based on simulations with dynamical chiral lattice fermions. We test properties and predictions that were put forward in the recent literature for models with Σ = 0, which include IR conformal theories. In particular, we probe the decorrelation of low lying Dirac eigenvalues, and we discuss the mass anomalous dimension and its IR extrapolation. Here, we encounter subtleties, which may urge caution with analogous efforts in other models, such as multi-flavor QCD.

APA, Harvard, Vancouver, ISO, and other styles

16

Dasmahapatra, Srinandan. "On the Combinatorics of Row and Corner Transfer Matrices of the $A^{(1)}_{n-1}$ Restricted Face Models." International Journal of Modern Physics A 12, no. 20 (August 10, 1997): 3551–86. http://dx.doi.org/10.1142/s0217751x97001845.

Full text

Abstract:

We establish a weight-preserving bijection between the index sets of the spectral data of row-to-row and corner transfer matrices for [Formula: see text] restricted interaction round a face (IRF) models. The evaluation of momenta by adding Takahashi integers in the spin chain language is shown to directly correspond to the computation of the energy of a path on the weight lattice in the two-dimensional model. As a consequence we derive fermionic forms of polynomial analogs of branching functions for the cosets [Formula: see text], and establish a bosonic–fermionic polynomial identity.

APA, Harvard, Vancouver, ISO, and other styles

17

van Dongen, P. G. J., and D. Vollhardt. "Exact mean-field Hamiltonian for fermionic lattice models in high dimensions." Physical Review Letters 65, no. 13 (September 24, 1990): 1663–66. http://dx.doi.org/10.1103/physrevlett.65.1663.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Athenodorou, A., E. Bennett, G. Bergner, and B. Lucini. "Recent results from SU(2) with one adjoint Dirac fermion." International Journal of Modern Physics A 32, no. 35 (December 20, 2017): 1747006. http://dx.doi.org/10.1142/s0217751x17470066.

Full text

Abstract:

We present some results for SU(2) with one adjoint Dirac flavour from the lattice studies. Data for the spectroscopy, the static potential, topological charge, and the anomalous dimension of the fermionic condensate are included. Our findings are found to be inconsistent with conventional confining behaviour, instead pointing tentatively towards a theory lying within or very near the onset of the conformal window, with an anomalous dimension of the fermionic condensate of almost 1. Implications of these findings on the building of models of strongly-interacting dynamics beyond the standard model are discussed.

APA, Harvard, Vancouver, ISO, and other styles

19

MELZER, EZER. "FERMIONIC CHARACTER SUMS AND THE CORNER TRANSFER MATRIX." International Journal of Modern Physics A 09, no. 07 (March 20, 1994): 1115–36. http://dx.doi.org/10.1142/s0217751x94000510.

Full text

Abstract:

We present a "natural finitization" of the fermionic q-series (certain generalizations of the Rogers–Ramanujan sums) which were recently conjectured to be equal to Virasoro characters of the unitary minimal conformal field theory (CFT) ℳ (p, p + 1). Within the quasi-particle interpretation of the fermionic q-series this finitization amounts to introducing an ultraviolet cutoff, which — contrary to a lattice spacing — does not modify the linear dispersion relation. The resulting polynomials are conjectured (proven, for p = 3, 4) to be equal to corner transfer matrix (CTM) sums which arise in the computation of order parameters in regime III of the r = p + 1 RSOS model of Andrews, Baxter and Forrester. Following Schur's proof of the Rogers–Ramanujan identities, these authors have shown that the infinite lattice limit of the CTM sums gives what later became known as the Rocha–Caridi formula for the Virasoro characters. Thus we provide a proof of the fermionic q-series representation for the Virasoro characters for p = 4 (the case p = 3 is "trivial"), in addition to extending the remarkable connection between CFT and off-critical RSOS models. We also discuss finitizations of the CFT modular-invariant partition functions.

APA, Harvard, Vancouver, ISO, and other styles

20

VAN DONGEN, P. G. J. "EXACT MEAN FIELD THEORY FOR CORRELATED LATTICE FERMIONS IN HIGH DIMENSIONS." Modern Physics Letters B 05, no. 13 (June 10, 1991): 861–69. http://dx.doi.org/10.1142/s0217984991001064.

Full text

Abstract:

We review the recently introduced concept of exact mean-field theories for fermionic lattice models. The method is applied to the Extended Simplified Hubbard Model, which is an Extended Hubbard model (including nearest-neighbor interaction) where only the ↓-electrons can hop. The construction of an exact mean-field Hamiltonian is discussed and a summary is given of the results obtained for the critical temperature, the order parameter and the density of states.

APA, Harvard, Vancouver, ISO, and other styles

21

Ranft, J., and A. Schiller. "Solitons with half-integral fermionic charge in (1+1)-dimensional hamiltonian lattice models." Nuclear Physics B 251 (January 1985): 764–88. http://dx.doi.org/10.1016/s0550-3213(85)80007-9.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Aoki, Yasumichi, Tatsumi Aoyama, Ed Bennett, Masafumi Kurachi, Toshihide Maskawa, Kohtaroh Miura, Kei-ichi Nagai, et al. "Lattice study of the scalar and baryon spectra in many-flavor QCD." International Journal of Modern Physics A 32, no. 35 (December 20, 2017): 1747010. http://dx.doi.org/10.1142/s0217751x17470108.

Full text

Abstract:

In the search for a composite Higgs boson in walking technicolor models, many flavor QCD, in particular with [Formula: see text], is an attractive candidate, and has been found to have a composite flavor-singlet scalar as light as the pion. Based on lattice simulations of this theory with the HISQ action, we will present our preliminary results on the scalar decay constant using the fermionic bilinear operator, and on the mass of the lightest baryon state which could be a dark matter candidate. Combining these two results, implications for dark matter direct detection are also discussed.

APA, Harvard, Vancouver, ISO, and other styles

23

Harnad, J., and A. Yu Orlov. "Fermionic construction of the partition function for multimatrix models and the multicomponent Toda lattice hierarchy." Theoretical and Mathematical Physics 152, no. 2 (August 2007): 1099–110. http://dx.doi.org/10.1007/s11232-007-0094-0.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

BELVEDERE, L. V., R. L. P. G. AMARAL, and A. F. DE QUEIROZ. "THE FERMION-BOSON MAPPING APPLIED TO LAGRANGIAN MODELS FOR CHARGE-DENSITY-WAVES IN ONE-DIMENSIONAL SYSTEMS." International Journal of Modern Physics B 16, no. 31 (December 10, 2002): 4685–716. http://dx.doi.org/10.1142/s0217979202014929.

Full text

Abstract:

We use the two-dimensional Fermion-Boson mapping to perform a field theory analysis of the effective Lagrangian model for incommensurate charge-density waves (ICDW) in one-dimensional systems. We consider an approach in which both the phase of the complex phonon field and the electron field are dynamical degrees of freedom contributing to the quantum dynamics and symmetry-related features of the ICDW phenomenon. We obtain the bosonized and fermionized versions of the effective electron–phonon Lagrangian. The phase of the phonon field and the phase of the bosonized chiral density of the electron field condense as a soliton order parameter, carrying neither the charge nor the chirality of the electron–phonon system, leading to a periodic sine-Gordon potential. The phonon field is fermionized in terms of a chiral fermionic condensate and the effective model is mapped into the chiral Gross–Neveu (GN) model with two Fermi field species. The linked electron–phonon symmetry of the ICDW system is mapped into the chiral symmetry of the GN model. Within the functional integral formulation, we obtain for the vacuum expectation value of the phonon field < ϕ > = 0 and < ϕ ϕ* > ≠ 0, due to the charge selection rule associated with the chiral electron–phonon symmetry. We show that the two-point correlation function of the phonon field satisfies the cluster decomposition property, as required by the chiral symmetry of the underlying GN model. The quantum description of the ICDW corresponds to charge transport through the lattice, due to the propagation of a "Goldstone mode" carrying the effective charge of the electron–phonon system, is accomplished by an electron–lattice energy redistribution. This accounts for a dynamical Peierls's energy gap generation.

APA, Harvard, Vancouver, ISO, and other styles

25

Davoudi, Zohreh, Alexander F. Shaw, and Jesse R. Stryker. "General quantum algorithms for Hamiltonian simulation with applications to a non-Abelian lattice gauge theory." Quantum 7 (December 20, 2023): 1213. http://dx.doi.org/10.22331/q-2023-12-20-1213.

Full text

Abstract:

With a focus on universal quantum computing for quantum simulation, and through the example of lattice gauge theories, we introduce rather general quantum algorithms that can efficiently simulate certain classes of interactions consisting of correlated changes in multiple (bosonic and fermionic) quantum numbers with non-trivial functional coefficients. In particular, we analyze diagonalization of Hamiltonian terms using a singular-value decomposition technique, and discuss how the achieved diagonal unitaries in the digitized time-evolution operator can be implemented. The lattice gauge theory studied is the SU(2) gauge theory in 1+1 dimensions coupled to one flavor of staggered fermions, for which a complete quantum-resource analysis within different computational models is presented. The algorithms are shown to be applicable to higher-dimensional theories as well as to other Abelian and non-Abelian gauge theories. The example chosen further demonstrates the importance of adopting efficient theoretical formulations: it is shown that an explicitly gauge-invariant formulation using loop, string, and hadron degrees of freedom simplifies the algorithms and lowers the cost compared with the standard formulations based on angular-momentum as well as the Schwinger-boson degrees of freedom. The loop-string-hadron formulation further retains the non-Abelian gauge symmetry despite the inexactness of the digitized simulation, without the need for costly controlled operations. Such theoretical and algorithmic considerations are likely to be essential in quantumly simulating other complex theories of relevance to nature.

APA, Harvard, Vancouver, ISO, and other styles

26

CLEMENTS, DAVID J., and ALON E. FARAGGI. "OPEN DESCENDANTS OF NAHE-BASED FREE FERMIONIC AND TYPE I ${\mathbb Z}_2^n$ MODELS." International Journal of Modern Physics A 19, no. 17n18 (July 20, 2004): 2931–70. http://dx.doi.org/10.1142/s0217751x04018464.

Full text

Abstract:

The NAHE set, that underlies the realistic free fermionic models, corresponds to ℤ2×ℤ2 orbifold at an enhanced symmetry point, with (h11,h21)=(27,3). Alternatively, a manifold with the same data is obtained by starting with a ℤ2×ℤ2 orbifold at a generic point on the lattice and adding a freely acting ℤ2 involution. In this paper we study type I orientifolds on the manifolds that underlie the NAHE-based models by incorporating such freely acting shifts. We present new models in the type I vacuum which are modulated by [Formula: see text] for n=2,3. In the case of n=2, the ℤ2×ℤ2 structure is a composite orbifold Kaluza–Klein shift arrangement. The partition function provides a simpler spectrum with chiral matter. For n=3, the case discussed is a ℤ2 modulation of the T6/ℤ2×ℤ2 spectrum. The additional projection shows an enhanced closed and open sector with chiral matter. The brane stacks are correspondingly altered from those which are present in the ℤ2×ℤ2 orbifold. In addition, we discuss the models arising from the open sector with and without discrete torsion.

APA, Harvard, Vancouver, ISO, and other styles

27

Uhrig, G., R. Strack, and D. Vollhardt. "Fermionic lattice models with internally competing symmetries: Nontrivial algebraic corrections in the Hartree-Fock ground-state energy." Physical Review B 46, no. 16 (October 15, 1992): 9940–45. http://dx.doi.org/10.1103/physrevb.46.9940.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Banchi, Leonardo, Enrico Compagno, Vladimir Korepin, and Sougato Bose. "Quantum gates between distant qubits via spin-independent scattering." Quantum 1 (November 30, 2017): 36. http://dx.doi.org/10.22331/q-2017-11-30-36.

Full text

Abstract:

We show how the spin independent scattering of two initially distant qubits, say, in distinct traps or in remote sites of a lattice, can be used to implement an entangling quantum gate between them. The scattering takes place under 1D confinement for which we consider two different scenarios: a 1D wave-guide and a tight-binding lattice. We consider models with contact-like interaction between two fermionic or two bosonic particles. A qubit is encoded in two distinct spins (or other internal) states of each particle. Our scheme enables the implementation of a gate between two qubits which are initially too far to interact directly, and provides an alternative to photonic mediators for the scaling of quantum computers. Fundamentally, an interesting feature is that "identical particles" (e.g., two atoms of the same species) and the 1D confinement, are both necessary for the action of the gate. Finally, we discuss the feasibility of our scheme, the degree of control required to initialize the wave-packets momenta, and show how the quality of the gate is affected by momentum distributions and initial distance. In a lattice, the control of quasi-momenta is naturally provided by few local edge impurities in the lattice potential.

APA, Harvard, Vancouver, ISO, and other styles

29

Calixto, Manuel, Alberto Mayorgas, and Julio Guerrero. "Hilbert Space Structure of the Low Energy Sector of U(N) Quantum Hall Ferromagnets and Their Classical Limit." Symmetry 14, no. 5 (April 24, 2022): 872. http://dx.doi.org/10.3390/sym14050872.

Full text

Abstract:

Using the Lieb–Mattis ordering theorem of electronic energy levels, we identify the Hilbert space of the low energy sector of U(N) quantum Hall/Heisenberg ferromagnets at filling factor M for L Landau/lattice sites with the carrier space of irreducible representations of U(N) described by rectangular Young tableaux of M rows and L columns, and associated with Grassmannian phase spaces U(N)/U(M)×U(N−M). We embed this N-component fermion mixture in Fock space through a Schwinger–Jordan (boson and fermion) representation of U(N)-spin operators. We provide different realizations of basis vectors using Young diagrams, Gelfand–Tsetlin patterns and Fock states (for an electron/flux occupation number in the fermionic/bosonic representation). U(N)-spin operator matrix elements in the Gelfand–Tsetlin basis are explicitly given. Coherent state excitations above the ground state are computed and labeled by complex (N−M)×M matrix points Z on the Grassmannian phase space. They adopt the form of a U(N) displaced/rotated highest-weight vector, or a multinomial Bose–Einstein condensate in the flux occupation number representation. Replacing U(N)-spin operators by their expectation values in a Grassmannian coherent state allows for a semi-classical treatment of the low energy (long wavelength) U(N)-spin-wave coherent excitations (skyrmions) of U(N) quantum Hall ferromagnets in terms of Grasmannian nonlinear sigma models.

APA, Harvard, Vancouver, ISO, and other styles

30

Calixto, Manuel, Alberto Mayorgas, and Julio Guerrero. "Hilbert Space Structure of the Low Energy Sector of U(N) Quantum Hall Ferromagnets and Their Classical Limit." Symmetry 14, no. 5 (April 24, 2022): 872. http://dx.doi.org/10.3390/sym14050872.

Full text

Abstract:

Using the Lieb–Mattis ordering theorem of electronic energy levels, we identify the Hilbert space of the low energy sector of U(N) quantum Hall/Heisenberg ferromagnets at filling factor M for L Landau/lattice sites with the carrier space of irreducible representations of U(N) described by rectangular Young tableaux of M rows and L columns, and associated with Grassmannian phase spaces U(N)/U(M)×U(N−M). We embed this N-component fermion mixture in Fock space through a Schwinger–Jordan (boson and fermion) representation of U(N)-spin operators. We provide different realizations of basis vectors using Young diagrams, Gelfand–Tsetlin patterns and Fock states (for an electron/flux occupation number in the fermionic/bosonic representation). U(N)-spin operator matrix elements in the Gelfand–Tsetlin basis are explicitly given. Coherent state excitations above the ground state are computed and labeled by complex (N−M)×M matrix points Z on the Grassmannian phase space. They adopt the form of a U(N) displaced/rotated highest-weight vector, or a multinomial Bose–Einstein condensate in the flux occupation number representation. Replacing U(N)-spin operators by their expectation values in a Grassmannian coherent state allows for a semi-classical treatment of the low energy (long wavelength) U(N)-spin-wave coherent excitations (skyrmions) of U(N) quantum Hall ferromagnets in terms of Grasmannian nonlinear sigma models.

APA, Harvard, Vancouver, ISO, and other styles

31

MIRONOV, A., and A. ZABRODIN. "THE ASYMPTOTICS OF THE CORRELATION FUNCTIONS IN (1+1)d QUANTUM FIELD THEORY FROM FINITE SIZE EFFECTS IN CONFORMAL THEORIES." International Journal of Modern Physics A 07, no. 16 (June 30, 1992): 3885–909. http://dx.doi.org/10.1142/s0217751x92001745.

Full text

Abstract:

Using the finite-size effects, the scaling dimensions and correlation functions of the main operators in continuous and lattice models of 1d spinless Bose-gas with pairwise interaction of rather general form are obtained. The long-wave properties of these systems can be described by the Gaussian model with central charge c=1. The disorder operators of the extended Gaussian model are found to correspond to some nonlocal operators in the XXZ Heisenberg antiferromagnet. This same approach is applicable to fermionic systems. Scaling dimensions of operators and correlation functions in the systems of interacting Fermi-particles are obtained. We present a universal treatment for 1d systems of different kinds which is independent of the exact integrability and which gives universal expressions for critical exponents through the thermodynamic characteristics of the system.

APA, Harvard, Vancouver, ISO, and other styles

32

Ma, Tian-Chi, Jing-Nan Hu, Yuan Chen, Lei Shao, Xian-Ru Hu, and Jian-Bo Deng. "Coexistence of type-II and type-IV Dirac fermions in SrAgBi." Modern Physics Letters B 35, no. 11 (February 9, 2021): 2150181. http://dx.doi.org/10.1142/s0217984921501815.

Full text

Abstract:

Relativistic massless Weyl and Dirac fermions have isotropic and linear dispersion relations to maintain Poincaré symmetry, which is the most basic symmetry in high-energy physics. The situation in condensed matter physics is less constrained; only certain subgroups of Poincaré symmetry — the 230 space groups that exist in 3D lattices — need be respected. Then, the free fermionic excitations that have no high-energy analogues could exist in solid state systems. Here, We discovered a type of nonlinear Dirac fermion without high-energy analogue in SrAgBi and named it type-IV Dirac fermion. The type-IV Dirac fermion has a nonlinear dispersion relationship and is similar to the type-II Dirac fermion, which has electron pocket and hole pocket. The effective model for the type-IV Dirac fermion is also found. It is worth pointing out that there is a type-II Dirac fermion near this new Dirac fermion. So we used two models to describe the coexistence of these two Dirac fermions. Topological surface states of these two Dirac points are also calculated. We envision that our findings will stimulate researchers to study novel physics of type-IV Dirac fermions, as well as the interplay of type-II and type-IV Dirac fermions.

APA, Harvard, Vancouver, ISO, and other styles

33

Bortone, Massimo, Yannic Rath, and George H. Booth. "Impact of conditional modelling for a universal autoregressive quantum state." Quantum 8 (February 8, 2024): 1245. http://dx.doi.org/10.22331/q-2024-02-08-1245.

Full text

Abstract:

We present a generalized framework to adapt universal quantum state approximators, enabling them to satisfy rigorous normalization and autoregressive properties. We also introduce filters as analogues to convolutional layers in neural networks to incorporate translationally symmetrized correlations in arbitrary quantum states. By applying this framework to the Gaussian process state, we enforce autoregressive and/or filter properties, analyzing the impact of the resulting inductive biases on variational flexibility, symmetries, and conserved quantities. In doing so we bring together different autoregressive states under a unified framework for machine learning-inspired ansätze. Our results provide insights into how the autoregressive construction influences the ability of a variational model to describe correlations in spin and fermionic lattice models, as well as ab initio electronic structure problems where the choice of representation affects accuracy. We conclude that, while enabling efficient and direct sampling, thus avoiding autocorrelation and loss of ergodicity issues in Metropolis sampling, the autoregressive construction materially constrains the expressivity of the model in many systems.

APA, Harvard, Vancouver, ISO, and other styles

34

KHOKHLACHEV, S., and YU MAKEENKO. "ADJOINT FERMIONS INDUCE QCD." Modern Physics Letters A 07, no. 39 (December 21, 1992): 3653–67. http://dx.doi.org/10.1142/s0217732392003086.

Full text

Abstract:

We propose to induce QCD by fermions in the adjoint representation of the gauge group SU (Nc) on the lattice. We consider various types of lattice fermions: chiral, Kogut-Susskind and Wilson ones. Using the mean field method we show that a first order large-N phase transition occurs with decreasing fermion mass. We conclude, therefore, that adjoint fermions induce QCD. We draw the same conclusion for the adjoint scalar or fermion models at large number of flavors Nf when they induce a single-plaquette lattice gauge theory. We find an exact strong coupling solution for the adjoint fermion model and show that it is quite similar to that for the Kazakov-Migdal model with the quadratic potential. We discuss the possibility for the adjoint fermion model to be solvable as Nc→∞ in the weak coupling region where the Wilson loops obey normal area law.

APA, Harvard, Vancouver, ISO, and other styles

35

DE WOUL, JONAS, and EDWIN LANGMANN. "FERMIONS IN TWO DIMENSIONS, BOSONIZATION, AND EXACTLY SOLVABLE MODELS." International Journal of Modern Physics B 26, no. 22 (July 26, 2012): 1244005. http://dx.doi.org/10.1142/s0217979212440055.

Full text

Abstract:

We discuss interacting fermion models in two dimensions, and, in particular, such that can be solved exactly by bosonization. One solvable model of this kind was proposed by Mattis as an effective description of fermions on a square lattice. We review recent work on a specific relation between a variant of Mattis' model and such a lattice fermion system, as well as the exact solution of this model. The background for this work includes well-established results for one-dimensional systems and the high-Tc problem. We also mention exactly solvable extensions of Mattis' model.

APA, Harvard, Vancouver, ISO, and other styles

36

Schaich, David, and Simon Catterall. "Phases of a strongly coupled four-fermion theory." EPJ Web of Conferences 175 (2018): 03004. http://dx.doi.org/10.1051/epjconf/201817503004.

Full text

Abstract:

We present ongoing investigations of a four-dimensional lattice field theory with four massless reduced staggered fermions coupled through an SU(4)-invariant fourfermion interaction. As in previous studies of four-fermion and Higgs–Yukawa models with different lattice fermion discretizations, we observe a strong-coupling phase in which the system develops a mass gap without breaking any lattice symmetry. This symmetric strong-coupling phase is separated from the symmetric weak-coupling phase by a narrow region of four-fermi coupling in which the system exhibits long-range correlations.

APA, Harvard, Vancouver, ISO, and other styles

37

Busill, R. J., and C. J. Thompson. "Variational bounds for lattice fermion models. I. Spinless fermions." Journal of Physics A: Mathematical and General 26, no. 12 (June 21, 1993): 2727–41. http://dx.doi.org/10.1088/0305-4470/26/12/014.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Li, Zi-Xiang, Abolhassan Vaezi, Christian B. Mendl, and Hong Yao. "Numerical observation of emergent spacetime supersymmetry at quantum criticality." Science Advances 4, no. 11 (November 2018): eaau1463. http://dx.doi.org/10.1126/sciadv.aau1463.

Full text

Abstract:

No definitive evidence of spacetime supersymmetry (SUSY) that transmutes fermions into bosons and vice versa has been revealed in nature so far. Moreover, the question of whether spacetime SUSY in 2 + 1 and higher dimensions can emerge in generic lattice microscopic models remains open. Here, we introduce a lattice realization of a single Dirac fermion in 2 + 1 dimensions with attractive interactions that preserves both time-reversal and chiral symmetries. By performing sign problem–free determinant quantum Monte Carlo simulations, we show that an interacting single Dirac fermion in 2 + 1 dimensions features a superconducting quantum critical point (QCP). We demonstrate that theN=2spacetime SUSY in 2 + 1 dimensions emerges at the superconducting QCP by showing that the fermions and bosons have identical anomalous dimensions 1/3, a hallmark of the emergent SUSY. We further show some experimental signatures that may be measured to test such emergent SUSY in candidate systems.

APA, Harvard, Vancouver, ISO, and other styles

39

CREUTZ, MICHAEL. "DIRECT SIMULATIONS OF SMALL MULTI-FERMION SYSTEMS." International Journal of Modern Physics C 14, no. 08 (October 2003): 1027–40. http://dx.doi.org/10.1142/s0129183103005169.

Full text

Abstract:

I explore computer simulations of the dynamics of small multi-fermion lattice systems. The method is more general, but I concentrate on Hubbard type models where the fermions hop between a small number of connected sites. I use the natural mapping of fermion occupation numbers onto computer bits. Signs from fermion interchange are reduced to bit counting. The technique inherently requires computer resources growing exponentially with the system volume; so, it restricted to modestly small systems. Large volume results would require combining these techniques with further approximations, perhaps in a recursive renormalization group manner.

APA, Harvard, Vancouver, ISO, and other styles

40

Hansen, Martin, Tadeusz Janowski, Claudio Pica, and Arianna Toniato. "SU(2) with fundamental fermions and scalars." EPJ Web of Conferences 175 (2018): 08010. http://dx.doi.org/10.1051/epjconf/201817508010.

Full text

Abstract:

We present preliminary results on the lattice simulation of an SU(2) gauge theory with two fermion flavors and one strongly interacting scalar field, all in the fundamental representation of SU(2). The motivation for this study comes from the recent proposal of “fundamental” partial compositeness models featuring strongly interacting scalar fields in addition to fermions. Here we describe the lattice setup for our study of this class of models and a first exploration of the lattice phase diagram. In particular we then investigate how the presence of a strongly coupled scalar field affects the properties of light meson resonances previously obtained for the SU(2) model. Preprint: CP3-Origins-2017-047 DNRF90

APA, Harvard, Vancouver, ISO, and other styles

41

Adebanjo, G. D., P. E. Kornilovitch, and J. P. Hague. "Superlight pairs in face-centred-cubic extended Hubbard models with strong Coulomb repulsion." Journal of Physics: Condensed Matter 34, no. 13 (January 19, 2022): 135601. http://dx.doi.org/10.1088/1361-648x/ac484e.

Full text

Abstract:

Abstract The majority of fulleride superconductors with unusually high transition-temperature to kinetic-energy ratios have a face-centred-cubic (FCC) structure. We demonstrate that, within extended Hubbard models with strong Coulomb repulsion, paired fermions in FCC lattices have qualitatively different properties than pairs in other three-dimensional cubic lattices. Our results show that strongly bound, light, and small pairs can be generated in FCC lattices across a wide range of the parameter space. We estimate that such pairs can Bose condense at high temperatures even if the lattice constant is large (as in the fullerides).

APA, Harvard, Vancouver, ISO, and other styles

42

Hasenfratz, A., R. C. Brower, C. Rebbi, E. Weinberg, and O. Witzel. "Strongly coupled gauge theories: What can lattice calculations teach us?" International Journal of Modern Physics A 32, no. 35 (December 20, 2017): 1747003. http://dx.doi.org/10.1142/s0217751x17470030.

Full text

Abstract:

The dynamical origin of electroweak symmetry breaking is an open question with many possible theoretical explanations. Strongly coupled systems predicting the Higgs boson as a bound state of a new gauge-fermion interaction form one class of candidate models. Due to increased statistics, LHC run II will further constrain the phenomenologically viable models in the near future. In the meanwhile it is important to understand the general properties and specific features of the different competing models. In this work we discuss many-flavor gauge-fermion systems that contain both massless (light) and massive fermions. The former provide Goldstone bosons and trigger electroweak symmetry breaking, while the latter indirectly influence the infrared dynamics. Numerical results reveal that such systems can exhibit a light [Formula: see text] isosinglet scalar, well separated from the rest of the spectrum. Further, when we set the scale via the vev of electroweak symmetry breaking, we predict a 2 TeV vector resonance which could be a generic feature of SU(3) gauge theories.

APA, Harvard, Vancouver, ISO, and other styles

43

Lyakhova, Ya S., E. A. Polyakov, and A. N. Rubtsov. "Restricted Boltzmann machine based on a Fermi sea." Journal of Physics A: Mathematical and Theoretical 54, no. 48 (November 11, 2021): 485302. http://dx.doi.org/10.1088/1751-8121/ac331d.

Full text

Abstract:

Abstract In recent years, there has been an intensive research on how to exploit the quantum laws of nature in the machine learning. Models have been put forward which employ spins, photons, and cold atoms. In this work we study the possibility of using the lattice fermions to learn the classical data. We propose an alternative to the quantum Boltzmann machine, the so-called spin-fermion machine (SFM), in which the spins represent the degrees of freedom of the observable data (to be learned), and the fermions represent the correlations between the data. The coupling is linear in spins and quadratic in fermions. The fermions are allowed to tunnel between the lattice sites. The training of SFM can be efficiently implemented since there are closed expressions for the log-likelihood gradient. We find that SFM is more powerful than the classical restricted Boltzmann machine with the same number of physical degrees of freedom. The reason is that SFM has additional freedom due to the rotation of the Fermi sea. We show examples for several data sets.

APA, Harvard, Vancouver, ISO, and other styles

44

Ho, Tin-Lun, and Qi Zhou. "Squeezing out the entropy of fermions in optical lattices." Proceedings of the National Academy of Sciences 106, no. 17 (April 13, 2009): 6916–20. http://dx.doi.org/10.1073/pnas.0809862105.

Full text

Abstract:

At present, there is considerable interest in using atomic fermions in optical lattices to emulate the mathematical models that have been used to study strongly correlated electronic systems. Some of these models, such as the 2-dimensional fermion Hubbard model, are notoriously difficult to solve, and their key properties remain controversial despite decades of studies. It is hoped that the emulation experiments will shed light on some of these long-standing problems. A successful emulation, however, requires reaching temperatures as low as 10−12 K and beyond, with entropy per particle far lower than what can be achieved today. Achieving such low-entropy states is an essential step and a grand challenge of the whole emulation enterprise. In this article, we point out a method to literally squeeze the entropy out from a Fermi gas into a surrounding Bose–Einstein condensed gas, which acts as a heat reservoir. This method allows one to reduce the entropy per particle of a lattice Fermi gas to a few percent of the lowest value obtainable today.

APA, Harvard, Vancouver, ISO, and other styles

45

Fendley, Paul, Bernard Nienhuis, and Kareljan Schoutens. "Lattice fermion models with supersymmetry." Journal of Physics A: Mathematical and General 36, no. 50 (December 1, 2003): 12399–424. http://dx.doi.org/10.1088/0305-4470/36/50/004.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Irkhin, Valentin Yu. "Ideas by S.V. Vonsovsky and Modern Model Treatment of Magnetism." Solid State Phenomena 168-169 (December 2010): 3–11. http://dx.doi.org/10.4028/www.scientific.net/ssp.168-169.3.

Full text

Abstract:

A review of fundamental works by Shubin and Vonsovsky on the formulation of the polar and s–d(f) exchange models is given. Their ideas are compared with subsequent developments in the theory of magnetism in d- and f-metals and their compounds. Modern approaches including various slave-boson and slave-fermion representations, formation of exotic quasiparticles etc. are discussed. Internal connections between different many-electron models (the Heisenberg, Hubbard, t–J, Anderson Hamiltonians) are presented. Description of anomalous rare-earth and actinide compounds (Kondo lattices, systems with heavy fermions and non-Fermi-liquid behavior) within the framework of the s–d(f) exchange model and related models is considered.

APA, Harvard, Vancouver, ISO, and other styles

47

Kassenova, Т. К. "PARAMETRIZED EIGHT-VERTEX MODEL AND KNOT INVARIANT." Eurasian Physical Technical Journal 19, no. 1 (39) (March 28, 2022): 119–26. http://dx.doi.org/10.31489/2022no1/119-126.

Full text

Abstract:

The article discusses and expands the known elements of the eight-vertex model, paying special attention to the parameterization of the matrix. The matrix values are interconnected with the knot through the braids and this model is valid on finite square lattices in two-dimensional space. A new solution of the parametrized eight-vertex model of free fermions with a complex version of elliptic functions, which is valid on a finite lattice, will be constructed. The range of applicability of the eight-vertex model with elements of the Jacobi elliptic function and the construction of a knot invariant on its basis is discussed by comparing the results obtained analytically for the model. The construction of the knot invariant using the Clebsch-Gordan coefficients and the main tool of statistical mechanics of the Yang-Baxter equation will be studied in detail

APA, Harvard, Vancouver, ISO, and other styles

48

Honecker and Richter. "Entropy of fermionic models on highly frustrated lattices." Condensed Matter Physics 8, no. 4 (2005): 813. http://dx.doi.org/10.5488/cmp.8.4.813.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Ilieva, N., H. Narnhofer, and W. Thirring. "Supersymmetric models for fermions on a lattice." Fortschritte der Physik 54, no. 2-3 (March 1, 2006): 124–38. http://dx.doi.org/10.1002/prop.200510261.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Müller-Hartmann, E. "FERMIONS ON A LATTICE IN HIGH DIMENSIONS." International Journal of Modern Physics B 03, no. 12 (December 1989): 2169–87. http://dx.doi.org/10.1142/s0217979289001391.

Full text

Abstract:

The limit of high dimensions of lattice fermion models has soon met great interest after its recent introduction by Metzner and Vollhardt. Fermion models are greatly simplified in high dimensions. The simplifications achieved are, however, much more subtle and diverse than those known for spin models. In the present contribution I present some of my own work as well as a short review of some other work on this new promising subject.

APA, Harvard, Vancouver, ISO, and other styles

We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!