The low-energy limiting behavior of the pseudofermion dynamical theory

Carmelo, J. M. P.; Martelo, L. M.; Penc, Karlo

doi:10.1016/j.nuclphysb.2005.12.016

Cited by 22 publications

(104 citation statements)

References 62 publications

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“…That allows going beyond the range of the exact solution alone and derive one-and two-electron spectral-weights and corresponding spectral-and correlation-function expressions for both low and finite energy 58,59 . Fortunately and as discussed in the following, in the low-energy limit such a general theory recovers the so called Tomonaga-Luttinger-liquid (TTL) behavior and anomalous scaling dimension of spin and charge correlations 60 .…”

Section: Charge and Spin Excitationsmentioning

confidence: 77%

“…Importantly, the studies of Ref. 60 reveal that when both momenta in the argument of such phase shifts lie at or near the c Fermi line and/or s1 boundary line, their square in units of 2π fully determines the anomalous dimensions of the primary fields of conformal-field theory. The low-energy physics of correlated 1D problems has some universal properties described by the TLL 65 .…”

Section: Charge and Spin Excitationsmentioning

confidence: 99%

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The square-lattice quantum liquid of charge c fermions and spin-neutral two-spinon s1 fermions

Carmelo

2010

Nuclear Physics B

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The momentum bands, energy dispersions, and velocities of the charge c fermions and spin-neutral two-spinon s1 fermions of a square-lattice quantum liquid referring to the Hubbard model on such a lattice of edge length L in the one-and two-electron subspace are studied. The model involves the effective nearest-neighbor integral t and on-site repulsion U and can be experimentally realized in systems of correlated ultra-cold fermionic atoms on an optical lattice and thus our results are of interest for such systems. Our investigations profit from a general rotated-electron description, which is consistent with the model global SO(3)×SO(3)×U (1) symmetry. For the model in the oneand two-electron subspace the discrete momentum values of the c and s1 fermions are good quantum numbers so that in contrast to the original strongly-correlated electronic problem their interactions are residual. The use of our description renders an involved many-electron problem into a quantum liquid with some similarities with a Fermi liquid. For the Hubbard model on a square lattice in the one-and two-electron subspace a composite s1 fermion consists of a spin-singlet spinon pair plus an infinitely thin flux tube attached to it. In the U/4t → ∞ limit of infinite on-site interaction the c fermions become non-interacting spinless fermions and the s1 fermion occupancy configurations that generate the spin degrees of freedom of spin-density m = 0 ground states become within a suitable mean-field approximation for the fictitious magnetic field Bs1 ex 3 brought about by the correlations of the original N electron problem those of a full lowest Landau level with N/2 degenerate one-s1 fermion states of the two-dimensional quantum Hall effect. In turn, for U/4t finite the degeneracy of the N/2 one-s1-fermion states is removed by the emergence of a finite-energy-bandwidth s1 fermion dispersion yet the number of s1 band discrete momentum values remains being given by Bs1 L 2 /Φ0 and the s1 effective lattice spacing by as1 = ls1/ √ 2π where ls1 is the fictitious-magnetic-field length and in our units the fictitious-magnetic-field flux quantum reads Φ0 = 1. Elsewhere it is found that the use of the square-lattice quantum liquid of charge c fermions and spin-neutral two-spinon s1 fermions investigated here contributes to the further understanding of the role of electronic correlations in the unusual properties of the hole-doped cuprate superconductors. This indicates that quantum-Hall-type behavior with or without magnetic field may be ubiquitous in nature.

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Section: Charge and Spin Excitationsmentioning

confidence: 77%

Section: Charge and Spin Excitationsmentioning

confidence: 99%

The square-lattice quantum liquid of charge c fermions and spin-neutral two-spinon s1 fermions

Carmelo

2010

Nuclear Physics B

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“…[4] and we calculate in this paper. Interestingly, the different expressions found here for the pre-factor F 0 (z) are such that the corresponding pre-factors of the space and time asymptotic expressions of correlation functions [7] are continuous functions of m as m → 0.…”

Section: Introductionmentioning

confidence: 74%

“…[2] and how a misprint in the latter equation becomes an error, by propagating to other expressions of Refs. [2,7].) The second case occurs when the excited states are such that for the functions on the right-hand side of Eq.…”

Section: ±1mentioning

confidence: 99%

Dynamical functions of a 1D correlated quantum liquid

Carmelo

Bozi

Penc

2008

J. Phys.: Condens. Matter

112

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Abstract. The dynamical correlation functions in the one-dimensional electronic systems show power-law behavior at low energies and momenta close to integer multiples of the charge and spin Fermi momenta. These systems are usually referred to as Tomonaga-Luttinger liquids. However, near well-dfined lines of the (k, ω) plane the power-law behaviour extends beyond the low-energy cases mentioned above, and also appears at higher energies leading to singular features in the photoemission spectra and other dynamical correlation functions. The general spectral-function expressions derived in this paper were used in recent theoretical studies of the finiteenergy singular features in photoemission of the organic compound tetrathiafulvalenetetracyanoquinodimethane (TTF-TCNQ) metallic phase. They are based on a so called pseudofermion dynamical theory (PDT), which allows us to systematically enumerate and describe the excitations in the Hubbard model starting from the Bethe-Ansatz, as well as to calculate the charge and spin objects phase shifts appearing as exponents of the power laws. In particular, we concentrate on the spin-density m → 0 limit and in effects of the vicinity of the singular border lines, as well as close to half filling. Our studies take into account spectral contributions from types of microscopic processes that do not occur for finite values of the spin density. In addition, the specific processes involved in the spectral features of TTF-TCNQ are studied. Our results are useful for the further understanding of the unusual spectral properties observed in low-dimensional organic metals and also provide expressions for the one-and twoatom spectral functions of a correlated quantum system of ultracold fermionic atoms in a 1D optical lattice with on-site two-atom repulsion.

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“…The method used in our theoretical analysis of the spin-charge separation observed in the 1D quantum-line defects of MoSe 2 was conceived for that specific goal. It combines the pseudofermion dynamical theory (PDT) for the 1D Hubbard model 24,27,37 with a suitable renormalisation procedure.…”

Section: Arpes Measurementsmentioning

confidence: 99%

Angle resolved photoemission spectroscopy reveals spin charge separation in metallic MoSe2 grain boundary

et al. 2017

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Material line defects are one-dimensional structures but the search and proof of electron behaviour consistent with the reduced dimension of such defects has been so far unsuccessful. Here we show using angle resolved photoemission spectroscopy that twin-grain boundaries in the layered semiconductor MoSe2 exhibit parabolic metallic bands. The one-dimensional nature is evident from a charge density wave transition, whose periodicity is given by kF/π, consistent with scanning tunnelling microscopy and angle resolved photoemission measurements. Most importantly, we provide evidence for spin- and charge-separation, the hallmark of one-dimensional quantum liquids. Our studies show that the spectral line splits into distinctive spinon and holon excitations whose dispersions exactly follow the energy-momentum dependence calculated by a Hubbard model with suitable finite-range interactions. Our results also imply that quantum wires and junctions can be isolated in line defects of other transition metal dichalcogenides, which may enable quantum transport measurements and devices.

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The low-energy limiting behavior of the pseudofermion dynamical theory

Cited by 22 publications

References 62 publications

The square-lattice quantum liquid of charge c fermions and spin-neutral two-spinon s1 fermions

The square-lattice quantum liquid of charge c fermions and spin-neutral two-spinon s1 fermions

Dynamical functions of a 1D correlated quantum liquid

Angle resolved photoemission spectroscopy reveals spin charge separation in metallic MoSe2 grain boundary

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