571 research outputs found
Fluctons
From the perspective of topological field theory we explore the physics
beyond instantons. We propose the fluctons as nonperturbative topological
fluctuations of vacuum, from which the self-dual domain of instantons is
attained as a particular case. Invoking the Atiyah-Singer index theorem, we
determine the dimension of the corresponding flucton moduli space, which gives
the number of degrees of freedom of the fluctons. An important consequence of
these results is that the topological phases of vacuum in non-Abelian gauge
theories are not necessarily associated with self-dual fields, but only with
smooth fields. Fluctons in different scenarios are considered, the basic
aspects of the quantum mechanical amplitude for fluctons are discussed, and the
case of gravity is discussed briefly
Pinwheels and nullhomologous surgery on 4-manifolds with b^+ = 1
We present a method for finding embedded nullhomologous tori in standard
4-manifolds which can be utilized to change their smooth structure. As an
application, we show how to obtain infinite families of simply connected smooth
4-manifolds with b^+ = 1 and b^- = 2,...,7, via surgery on nullhomologous tori
embedded in the standard manifolds CP^2 # k (-CP^2), k=2,...,7.Comment: Final version. To appear in AG
Saddle point solutions in Yang-Mills-dilaton theory
The coupling of a dilaton to the -Yang-Mills field leads to
interesting non-perturbative static spherically symmetric solutions which are
studied by mixed analitical and numerical methods. In the abelian sector of the
theory there are finite-energy magnetic and electric monopole solutions which
saturate the Bogomol'nyi bound. In the nonabelian sector there exist a
countable family of globally regular solutions which are purely magnetic but
have zero Yang-Mills magnetic charge. Their discrete spectrum of energies is
bounded from above by the energy of the abelian magnetic monopole with unit
magnetic charge. The stability analysis demonstrates that the solutions are
saddle points of the energy functional with increasing number of unstable
modes. The existence and instability of these solutions are "explained" by the
Morse-theory argument recently proposed by Sudarsky and Wald.Comment: 11 page
Expansion in the distance parameter for two vortices close together
Static vortices close together are studied for two different models in
2-dimen- sional Euclidean space. In a simple model for one complex field an
expansion in the parameters describing the relative position of two vortices
can be given in terms of trigonometric and exponential functions. The results
are then compared to those of the Ginzburg-Landau theory of a superconductor in
a magnetic field at the point between type-I and type-II superconductivity. For
the angular dependence a similar pattern emerges in both models. The
differences for the radial functions are studied up to third order.Comment: 14 pages, Late
Enumerative geometry of Calabi-Yau 4-folds
Gromov-Witten theory is used to define an enumerative geometry of curves in
Calabi-Yau 4-folds. The main technique is to find exact solutions to moving
multiple cover integrals. The resulting invariants are analogous to the BPS
counts of Gopakumar and Vafa for Calabi-Yau 3-folds. We conjecture the 4-fold
invariants to be integers and expect a sheaf theoretic explanation.
Several local Calabi-Yau 4-folds are solved exactly. Compact cases, including
the sextic Calabi-Yau in CP5, are also studied. A complete solution of the
Gromov-Witten theory of the sextic is conjecturally obtained by the holomorphic
anomaly equation.Comment: 44 page
Notes on bordered Floer homology
This is a survey of bordered Heegaard Floer homology, an extension of the
Heegaard Floer invariant HF-hat to 3-manifolds with boundary. Emphasis is
placed on how bordered Heegaard Floer homology can be used for computations.Comment: 73 pages, 29 figures. Based on lectures at the Contact and Symplectic
Topology Summer School in Budapest, July 2012. v2: Fixed many small typo
Precise Determination of Electroweak Parameters in Neutrino-Nucleon Scattering
A systematic error in the extraction of from nuclear deep
inelastic scattering of neutrinos and antineutrinos arises from higher-twist
effects arising from nuclear shadowing. We explain that these effects cause a
correction to the results of the recently reported significant deviation from
the Standard Model that is potentially as large as the deviation claimed, and
of a sign that cannot be determined without an extremely careful study of the
data set used to model the input parton distribution functions.Comment: 3pages, 0 figures, version to be published by IJMP
Telescopic actions
A group action H on X is called "telescopic" if for any finitely presented
group G, there exists a subgroup H' in H such that G is isomorphic to the
fundamental group of X/H'.
We construct examples of telescopic actions on some CAT[-1] spaces, in
particular on 3 and 4-dimensional hyperbolic spaces. As applications we give
new proofs of the following statements:
(1) Aitchison's theorem: Every finitely presented group G can appear as the
fundamental group of M/J, where M is a compact 3-manifold and J is an
involution which has only isolated fixed points;
(2) Taubes' theorem: Every finitely presented group G can appear as the
fundamental group of a compact complex 3-manifold.Comment: +higher dimension
Supercharges, Quantum States and Angular Momentum for N=4 Supersymmetric Monopoles
We revisit the moduli space approximation to the quantum mechanics of
monopoles in N=4 supersymmetric Yang-Mills-Higgs theory with maximal symmetry
breaking. Starting with the observation that the set of fermionic zero-modes in
N=4 supersymmetric Yang-Mills-Higgs theory can be viewed as two copies of the
set of fermionic zero-modes in the N=2 version, we build a model to describe
the quantum mechanics of N=4 supersymmetric monopoles, based on our previous
paper [1] on the N=2 case, in which this doubling of fermionic zero-modes is
manifest throughout. Our final picture extends the familiar result that quantum
states are described by differential forms on the moduli space and that the
Hamiltonian operator is the Laplacian acting on forms. In particular, we derive
a general expression for the total angular momentum operator on the moduli
space which differs from the naive candidate by the adjoint action of the
complex structures. We also express all the supercharges in terms of (twisted)
Dolbeault operators and illustrate our results by discussing, in some detail,
the N=4 supersymmetric quantum dynamics of monopoles in a theory with gauge
group SU(3) broken to U(1) x U(1).Comment: Updated references, included a derivation of the angular momentum
operator, 32 page
Only hybrid anyons can exist in broken symmetry phase of nonrelativistic Chern-Simons theory
We present two examples of parity-invariant Chern-Simons-Higgs
models with spontaneously broken symmetry. The models possess topological
vortex excitations. It is argued that the smallest possible flux quanta are
composites of one quantum of each type . These hybrid anyons will
dominate the statistical properties near the ground state. We analyse their
statistical interactions and find out that unlike in the case of Jackiw-Pi
solitons there is short range magnetic interaction which can lead to formation
of bound states of hybrid anyons. In addition to mutual interactions they
possess internal structure which can lead upon quantisation to discrete
spectrum of energy levels.Comment: 10 pages in plain Latex (one argument added, version accepted for
publication in Phys.Rev.D(Rapid Communications)
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