共查询到20条相似文献,搜索用时 15 毫秒
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We compute the axial anomaly of a Lifshitz fermion theory with anisotropic scaling z = 3 which is minimally coupled to geometry in 3+1 space‐time dimensions. We find that the result is identical to the relativistic case using path integral methods. An independent verification is provided by showing with spectral methods that the η‐invariant of the Dirac and Lifshitz fermion operators in three dimensions are equal. Thus, by the integrated form of the anomaly, the index of the Dirac operator still accounts for the possible breakdown of chiral symmetry in non‐relativistic theories of gravity. We apply this framework to the recently constructed gravitational instanton backgrounds of Hořava–Lifshitz theory and find that the index is non‐zero provided that the space‐time foliation admits leaves with harmonic spinors. Using Hitchin's construction of harmonic spinors on Berger spheres, we obtain explicit results for the index of the fermion operator on all such gravitational instanton backgrounds with SU(2) × U(1) isometry. In contrast to the instantons of Einstein gravity, chiral symmetry breaking becomes possible in the unimodular phase of Hořava–Lifshitz theory arising at λ = 1/3 provided that the volume of space is bounded from below by the ratio of the Ricci to Cotton tensor couplings raised to the third power. Some other aspects of the anomalies in non‐relativistic quantum field theories are also discussed. 相似文献
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《Nuclear Physics B》1988,301(1):115-131
We derive, by an algebraic method, a manifestly supersymmetric extension of Bardeen's minimal form of axial anomalies, which obeys the Wess-Zumino consistency condition. The left-right symmetric form of the anomalies is also obtained by a reduction procedure. We construct the supersymmetric Wess-Zumino effective action and study its low-energy features. 相似文献
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Yamazaki T Aoki Y Blum T Lin HW Lin MF Ohta S Sasaki S Tweedie RJ Zanotti JM;RBC+UKQCD Collaborations 《Physical review letters》2008,100(17):171602
We present results for the nucleon axial charge g{A} at a fixed lattice spacing of 1/a=1.73(3) GeV using 2+1 flavors of domain wall fermions on size 16;{3} x 32 and 24;{3} x 64 lattices (L=1.8 and 2.7 fm) with length 16 in the fifth dimension. The length of the Monte Carlo trajectory at the lightest m_{pi} is 7360 units, including 900 for thermalization. We find finite volume effects are larger than the pion mass dependence at m{pi}=330 MeV. We also find a scaling with the single variable m{pi}L which can also be seen in previous two-flavor domain wall and Wilson fermion calculations. Using this scaling to eliminate the finite-volume effect, we obtain g{A}=1.20(6)(4) at the physical pion mass, m_{pi}=135 MeV, where the first and second errors are statistical and systematic. The observed finite-volume scaling also appears in similar quenched simulations, but disappear when V>or=(2.4 fm);{3}. We argue this is a dynamical quark effect. 相似文献
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Walter Selke 《Physics letters. A》1977,61(7):443-444
Lifshitz points of higher character are found for the spherical model with multi-neighbour interactions. The Lifshitz point of character three is a point of intersection of lines of first and second order transitions. 相似文献
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It is shown that a novel anomaly associated with transverse Ward-Takahashi identity exists for a pseudotensor current in QED, and the anomaly gives rise to a topological index of a Dirac operator in terms of an AtiyahSinger index theorem. 相似文献
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The electronic structure of graphitic cones is investigated within the self-consistent field-theory model. The local and total density of states near the apex are found for cones of different opening angles. For extended electronic states, the total density of states is found to vanish at the Fermi level at any opening angles more than 60° In turn, for power-law localized states, normalized zero-energy modes are shown to emerge. 相似文献
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Peter Stollmann 《Mathematical Physics, Analysis and Geometry》1999,2(3):279-289
We present a simple method for proving Lifshitz asymptotics for random Schrödinger operators and apply it to the Anderson and Poisson model. 相似文献
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We investigate several aspects of exact black hole solutions in asymptotically Lifshitz spacetime. Firstly,we calculate the tidal forces and find that in the near horizon region of such black hole backgrounds, the tidal forces diverge in the near extremal limit. Secondly, we evaluate the Wilson loops in both extremal and finite temperature cases. Finally, we obtain the corresponding shear viscosity and square of the sound speed and find that the ratio of shear viscosity to entropy density takes the universal value 1/4π in arbitrary dimensions while the square of the speed of sound saturates the conjectured bound 1/3 in five dimensions. 相似文献
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PANG Da-Wei 《理论物理通讯》2014,62(2):265-271
We investigate several aspects of exact black hole solutions in asymptotically Lifshitz spacetime. Firstly, we calculate the tidal forces and find that in the near horizon region of such black hole backgrounds, the tidal forces diverge in the near extremal limit. Secondly, we evaluate the Wilson loops in both extremal and finite temperature cases. Finally, we obtain the corresponding shear viscosity and square of the sound speed and find that the ratio of shear viscosity to entropy density takes the universal value 1/4π in arbitrary dimensions while the square of the speed of sound saturates the conjectured bound 1/3 in five dimensions. 相似文献
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A model of strongly correlated spinless fermions on a checkerboard lattice is mapped onto a quantum fully packed loop model. We identify a large number of fluctuationless states specific to the fermionic case. We also show that for a class of fluctuating states the fermionic sign problem can be gauged away. This claim is supported by numerical evaluation of the low-lying states. Furthermore, we analyze excitations at the Rokhsar-Kivelson point of this model using the relation to the height model and the single-mode approximation. 相似文献
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A version of euclidean lattice QCD obtained by introducing the fermions using Susskind's method is described and certain properties discussed. A U(1) axial current having the correct axial anomaly in the continuum limit is identified. We find for SU(3) with 4 flavors. 相似文献
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Andrzej M. Szczerba 《Communications in Mathematical Physics》1985,98(4):513-524
It is proved that the system of free fermions on arbitrary lattices is equivalent to the set of locally interacting constrained spins. The fermionic counterpart of the unconstrained spin system is also derived. The generalization to the interacting theories is possible. 相似文献
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