共查询到20条相似文献,搜索用时 15 毫秒
1.
We discuss the implications of approximate particle-hole symmetry in a half-filled Landau level in which a paired quantum Hall state forms. We note that the Pfaffian state is not particle-hole symmetric. Therefore, in the limit of vanishing Landau-level mixing, in which particle-hole transformation is an exact symmetry, the Pfaffian spontaneously breaks this symmetry. There is a particle-hole conjugate state, which we call the anti-Pfaffian, which is degenerate with the Pfaffian in this limit. We observe that strong Landau-level mixing should favor the Pfaffian, but it is an open problem which state is favored for the moderate Landau-level mixing which is present in experiments. We discuss the bulk and edge physics of the anti-Pfaffian. We analyze a simplified model in which transitions between analogs of the two states can be studied in detail. Finally, we discuss experimental implications. 相似文献
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The understanding of the interplay of electron correlations and randomness in solids is enhanced by demonstrating that particle-hole ( p-h) symmetry plays a crucial role in determining the effects of disorder on the transport and thermodynamic properties of the half-filled Hubbard Hamiltonian. We show that the low-temperature conductivity decreases with increasing disorder when p-h symmetry is preserved, and shows the opposite behavior, i.e., conductivity increases with increasing disorder, when p-h symmetry is broken. The Mott insulating gap is insensitive to weak disorder when there is p-h symmetry, whereas in its absence the gap diminishes with increasing disorder. 相似文献
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Here, we show that the incompressible Pfaffian state originally proposed for the 5/2 fractional quantum Hall states in conventional two-dimensional electron systems can actually be found in a bilayer graphene at one of the Landau levels. The properties and stability of the Pfaffian state at this special Landau level strongly depend on the magnetic field strength. The graphene system shows a transition from the incompressible to a compressible state with increasing magnetic field. At a finite magnetic field of ~10 T, the Pfaffian state in bilayer graphene becomes more stable than its counterpart in conventional electron systems. 相似文献
5.
《Nuclear Physics A》1986,453(1):127-140
An analytical relation is derived for the density of particle-hole bound states applying the equidistant-spacing approximation and the Darwin-Fowler statistical method. The Pauli exclusion principle as well as the finite depth of the potential well are taken into account. The set of densities needed for calculations of multi-step compound reactions is completed by deriving the densities of accessible final states for escape and damping. 相似文献
6.
Analytical formulae have been derived for the density of particle-hole states having all particles bound. Such states are involved in the statistical multi-step compound MSC emission. Results of calculations are compared with predictions of other theoretical approaches. 相似文献
7.
A formula is derived for the density of particle-hole states in the equidistant spacing model.The effect of the Pauli exclusion principle is exactly taken into acount.The pairing effect as well as two energy constraints are involved.The formula is suited for calculating.Comparisons of the results imply that the Pauli effect and the pairing effect play an important role in particle-hole state density. 相似文献
8.
《Nuclear Physics B》1998,516(3):704-718
We present a low-energy effective field theory describing the universality class of the Pfaffian quantum Hall state. To arrive at this theory, we observe that the edge theory of the Pfaffian state of bosons at v = 1 is an SU(2)2 Kac-Moody algebra. It follows that the corresponding bulk effective field theory is an SU(2) Chem-Simons theory with coupling constant k = 2. The effective field theories for other Pfaffian states, such as the fermionic one at v = 1/2 are obtained by a flux-attachment procedure. We discuss the non-Abelian statistics of quasiparticles in the context of this effective field theory. 相似文献
9.
John Palmer 《Communications in Mathematical Physics》1989,120(4):547-574
An infinite volume Pfaffian formalism is developed for the Ising model.Research supported in part by NSF grant DMS-8421289 相似文献
10.
It is shown that the seminal Horodecki 2-qutrit state belongs to the class of states displaying symmetry governed by a commutative subgroup of the unitary group U(3). Taking a conjugate subgroup one obtains another classes of symmetric states and one finds equivalent representations of the Horodecki state. These results are generalized to d⊗d systems. 相似文献
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Aokage Kazuya Shinkawa Eriko Yamada Hiro-Fumi 《Letters in Mathematical Physics》2020,110(6):1381-1389
Letters in Mathematical Physics - A formula for Schur Q-functions is presented which describes the action of the Virasoro operators. For a strict partition $$\lambda =(\lambda _1,\lambda _2,\ldots... 相似文献
13.
Spontaneous time-reversal symmetry breaking plays an important role in studying strongly correlated unconventional superconductors.When two superconducting gap functions with different symmetries compete,the relative phase channel(θ-≡θ1-θ2)exhibits an Ising-type Z2 symmetry due to the second order Josephson coupling,where θ1,2 are the phases of two gap functions.In contrast,the U(1) symmetry in the channel of θ+≡(θ1+θ 相似文献
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V. M. Kolomietz A. I. Sanzhur 《The European Physical Journal A - Hadrons and Nuclei》2008,38(3):345-354
We apply the direct variational method to derive the equation of state for finite nuclei within the stability valley. The
extended Thomas-Fermi approximation for the energy functional with Skyrme forces is used. Applying the leptodermous expansion
for the profile nucleon densities, we have studied the neutron coat and the isospin symmetry energy for neutron-rich nuclei.
Using the equation of state for the pressure, we derive the region of spinodal instability of finite nuclei and its dependence
on the mass number, the asymmetry parameter and the Skyrme force parameters. We suggest the procedure of derivation of the
isospin symmetry energy from the analysis of the isospin shift of the chemical potential
= - beyond the beta-stability line. We show that both the structure of the neutron coat and the position of the drip line depend
significantly on the Skyrme force parameters. 相似文献
16.
T. Domański 《The European Physical Journal B - Condensed Matter and Complex Systems》2010,74(4):437-445
Development of the STM and ARPES spectroscopy enabled to reach
the resolution sufficient for probing the particle-hole entanglement
in superconducting materials, even above the critical temperature
Tc. On a quantitative level one can characterize such
entanglement in terms of the Bogoliubov angle which determines
to what extent the particles and holes constitute the effective
quasiparticles.
In classical superconductors, where the phase transition is related
to formation of the Cooper pairs almost simultaneously accompanied
by onset of their long-range phase coherence, the Bogoliubov angle
is slanted (due to finite particle-hole mixing) all the way up to Tc.
In the high temperature superconductors and in superfluid ultracold
fermion atoms near the Feshbach resonance the situation is different
because the preformed pairs can exist above Tc albeit
loosing coherence due to the strong quantum fluctuations. We
discuss a generic temperature dependence of the Bogoliubov angle
in such pseudogap state indicating a novel, non-BCS behavior. For
analysis we use the two-component model describing the pairs
coexisting with single fermions and study selfconsistently
their feedback effects by the similarity transformation
originating from the renormalization group approach. 相似文献
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H. Machner 《Zeitschrift für Physik A Hadrons and Nuclei》1985,321(4):577-580
Nucleus-nucleus collisions lead to nuclear excitations which can be expressed in terms of particles and holes. An empirical formula is presented to calculate this initially degree of freedom. The formula is tested against data and found to have a large range of validity with respect to projectile masses and bombarding energies. 相似文献
19.
Equations and relations are discussed which allow to calculate particle-hole amplitudes of excited states of spherical nuclei. In particular we investigate the case where the Bethe-Salpeter equation must be solved in both particle-hole channels. 相似文献
20.
《Physics letters. A》1997,228(6):383-390
By applying the partial particle-hole and the particle-hole unitary transformations to the Hubbard model, we establish several new sum rules for the Hubbard model defined on a bipartite lattice. 相似文献