1,861 research outputs found
A Unified Conformal Field Theory Description of Paired Quantum Hall States
The wave functions of the Haldane-Rezayi paired Hall state have been
previously described by a non-unitary conformal field theory with central
charge c=-2. Moreover, a relation with the c=1 unitary Weyl fermion has been
suggested. We construct the complete unitary theory and show that it
consistently describes the edge excitations of the Haldane-Rezayi state.
Actually, we show that the unitary (c=1) and non-unitary (c=-2) theories are
related by a local map between the two sets of fields and by a suitable change
of conjugation. The unitary theory of the Haldane-Rezayi state is found to be
the same as that of the 331 paired Hall state. Furthermore, the analysis of
modular invariant partition functions shows that no alternative unitary
descriptions are possible for the Haldane-Rezayi state within the class of
rational conformal field theories with abelian current algebra. Finally, the
known c=3/2 conformal theory of the Pfaffian state is also obtained from the
331 theory by a reduction of degrees of freedom which can be physically
realized in the double-layer Hall systems.Comment: Latex, 42 pages, 2 figures, 3 tables; minor corrections to text and
reference
Study of Apollo water impact. Volume 8 - Unsymmetric shells of revolution analysis Final report
Numerical analysis of static, and dynamic shell response to water impact load
(2+1)-Gravity with Moving Particles in an Instantaneous Gauge
By defining a regular gauge which is conformal-like and provides
instantaneous field propagation, we investigate classical solutions of
(2+1)-Gravity coupled to arbitrarily moving point-like particles. We show how
to separate field equations from self-consistent motion and we provide a
solution for the metric and the motion in the two-body case with arbitrary
speed, up to second order in the mass parameters.Comment: 16 pages, LaTeX, no figure
Non-Perturbative Particle Dynamics
We construct a non-perturbative, single-valued solution for the metric and
the motion of two interacting particles in ()-Gravity, by using a Coulomb
gauge of conformal type. The method provides the mapping from multivalued (
minkowskian ) coordinates to single-valued ones, which solves the non-abelian
monodromies due to particles's momenta and can be applied also to the general
N-body case.Comment: 11 pages, LaTeX, no figure
The W_N minimal model classification
We first rigourously establish, for any N, that the toroidal modular
invariant partition functions for the (not necessarily unitary) W_N(p,q)
minimal models biject onto a well-defined subset of those of the SU(N)xSU(N)
Wess-Zumino-Witten theories at level (p-N,q-N). This permits considerable
simplifications to the proof of the Cappelli-Itzykson-Zuber classification of
Virasoro minimal models. More important, we obtain from this the complete
classification of all modular invariants for the W_3(p,q) minimal models. All
should be realised by rational conformal field theories. Previously, only those
for the unitary models, i.e. W_3(p,p+1), were classified. For all N our
correspondence yields for free an extensive list of W_N(p,q) modular
invariants. The W_3 modular invariants, like the Virasoro minimal models, all
factorise into SU(3) modular invariants, but this fails in general for larger
N. We also classify the SU(3)xSU(3) modular invariants, and find there a new
infinite series of exceptionals.Comment: 25 page
't Hooft Anomaly Matching Conditions for Generalized Symmetries in 2D
The 't Hooft anomaly matching conditions are a standard tool to study and
test non-perturbative issues in quantum field theory. We give a new, simple
proof of the anomaly matching conditions in 2D Poincare` invariant theories. We
consider the case of invariance under a large class of generalized symmetries,
which include abelian and non-abelian internal symmetries, space-time
symmetries generated by the stress tensor, and W-type of symmetries generated
by higher spin currents.Comment: 10 pages, TeX, corrected minor misprints in text and reference
A new class of Matrix Models arising from the W-infinity Algebra
We present a new class of hermitian one-matrix models originated in the
W-infinity algebra: more precisely, the polynomials defining the W-infinity
generators in their fermionic bilinear form are shown to expand the orthogonal
basis of a class of random hermitian matrix models. The corresponding
potentials are given, and the thermodynamic limit interpreted in terms of a
simple plasma picture. The new matrix models can be successfully applied to the
full bosonization of interesting one-dimensional systems, including all the
perturbative orders in the inverse size of the system. As a simple application,
we present the all-order bosonization of the free fermionic field on the
one-dimensional lattice.Comment: 8 pages, 1 figur
Quantum Field Theory Anomalies in Condensed Matter Physics
We give a pedagogical introduction to quantum anomalies, how they are
calculated using various methods, and why they are important in condensed
matter theory. We discuss axial, chiral, and gravitational anomalies as well as
global anomalies. We illustrate the theory with examples such as quantum Hall
liquids, Fermi liquids, Weyl semi-metals, topological insulators and
topological superconductors. The required background is basic knowledge of
quantum field theory, including fermions and gauge fields, and some familiarity
with path integral and functional methods. Some knowledge of topological phases
of matter is helpful, but not necessary.Comment: Lecture notes. 142 pages, 24 figures. Please send comment
Thermal broadening of the Coulomb blockade peaks in quantum Hall interferometers
We demonstrate that the differential magnetic susceptibility of a fractional
quantum Hall disk, representing a Coulomb island in a Fabry--Perot
interferometer, is exactly proportional to the island's conductance and its
paramagnetic peaks are the equilibrium counterparts of the Coulomb blockade
conductance peaks. Using as a thermodynamic potential the partition functions
of the edge states' effective conformal field theory we find the positions of
the Coulomb blockade peaks, when the area of the island is varied, the
modulations of the distance between them as well as the thermal decay and
broadening of the peaks when temperature is increased. The finite-temperature
estimates of the peak's heights and widths could give important information
about the experimental observability of the Coulomb blockade. In addition, the
predicted peak asymmetry and displacement at finite temperature due to neutral
multiplicities could serve to distinguish different fractional quantum Hall
states with similar zero-temperature Coulomb blockade patterns.Comment: 6 pages, 6 figures; published versio
Chiral persistent currents and magnetic susceptibilities in the parafermion quantum Hall states in the second Landau level with Aharonov-Bohm flux
Using the effective conformal field theory for the quantum Hall edge states
we propose a compact and convenient scheme for the computation of the periods,
amplitudes and temperature behavior of the chiral persistent currents and the
magnetic susceptibilities in the mesoscopic disk version of the Z_k parafermion
quantum Hall states in the second Landau level. Our numerical calculations show
that the persistent currents are periodic in the Aharonov-Bohm flux with period
exactly one flux quantum and have a diamagnetic nature. In the high-temperature
regime their amplitudes decay exponentially with increasing the temperature and
the corresponding exponents are universal characteristics of non-Fermi liquids.
Our theoretical results for these exponents are in perfect agreement with those
extracted from the numerical data and demonstrate that there is in general a
non-trivial contribution coming from the neutral sector. We emphasize the
crucial role of the non-holomorphic factors, first proposed by Cappelli and
Zemba in the context of the conformal field theory partition functions for the
quantum Hall states, which ensure the invariance of the annulus partition
function under the Laughlin spectral flow.Comment: 14 pages, RevTeX4, 7 figures (eps
- …