pinecone/core-2020-05-10-deduplication huggingface dataset:
The Yangian origin of the Grassmannian integral

In this paper we analyse formulas which reproduce different contributions to
scattering amplitudes in N=4 super Yang-Mills theory through a Grassmannian
integral. Recently their Yangian invariance has been proved directly by using
the explicit expression of the Yangian level-one generators. The specific
cyclic structure of the form integrated over the Grassmannian enters in a
crucial way in demonstrating the symmetry. Here we show that the Yangian
symmetry fixes this structure uniquely.Comment: 26 pages. v2: typos corrected, published versio
Semiclassical Analysis of M2-brane in AdS_4 x S^7 / Z_k

We start from the classical action describing a single M2-brane on AdS_4 x
S^7/ Z_k and consider semiclassical fluctuaitions around a static, 1/2 BPS
configuration whose shape is AdS_2 x S^1. The internal manifold S^7/ Z_k is
described as a U(1) fibration over CP^3 and the static configuration is wrapped
on the U(1) fiber. Then the configuration is reduced to an AdS_2 world-sheet of
type IIA string on AdS_4 x CP^3 through the Kaluza-Klein reduction on the S^1.
It is shown that the fluctuations form an infinite set of N=1 supermultiplets
on AdS_2, for k=1,2. The set is invariant under SO(8) which may be consistent
with N=8 supersymmetry on AdS_2. We discuss the behavior of the fluctuations
around the boundary of AdS_2 and its relation to deformations of Wilson loop
operator.Comment: 27 pages, v2: references added, v3: major revision including the
  clarification of k=2 case, references added, version to appear in JHE
Numerical NLO QCD calculations

We present an algorithm for the numerical calculation of one-loop QCD
amplitudes. The algorithm consists of subtraction terms, approximating the
soft, collinear and ultraviolet divergences of one-loop amplitudes and a method
to deform the integration contour for the loop integration into the complex
space. The algorithm is formulated at the amplitude level and does not rely on
Feynman graphs. Therefore all required ingredients can be calculated
efficiently using recurrence relations. The algorithm applies to massless
partons as well as to massive partons.Comment: 62 pages, version to be publishe
Spiky Strings and Giant Holes

We analyse semiclassical strings in AdS in the limit of one large spin. In
this limit, classical string dynamics is described by a finite number of
collective coordinates corresponding to spikes or cusps of the string. The
semiclassical spectrum consists of two branches of excitations corresponding to
"large" and "small" spikes respectively. We propose that these states are dual
to the excitations known as large and small holes in the spin chain description
of N=4 SUSY Yang-Mills. The dynamics of large spikes in classical string theory
can be mapped to that of a classical spin chain of fixed length. In turn, small
spikes correspond to classical solitons propagating on the background formed by
the large spikes. We derive the dispersion relation for these excitations
directly in the finite gap formalism.Comment: 36 pages, 9 figure
Flavour in supersymmetry: horizontal symmetries or wave function
  renormalisation

We compare theoretical and experimental predictions of two main classes of
models addressing fermion mass hierarchies and flavour changing neutral
currents (FCNC) effects in supersymmetry: Froggatt-Nielsen (FN) U(1) gauged
flavour models and Nelson-Strassler/extra dimensional models with hierarchical
wave functions for the families. We show that whereas the two lead to identical
predictions in the fermion mass matrices, the second class generates a stronger
suppression of FCNC effects. We prove that, whereas at first sight the FN setup
is more constrained due to anomaly cancelation conditions, imposing unification
of gauge couplings in the second setup generates conditions which precisely
match the mixed anomaly constraints in the FN setup. Finally, we provide an
economical extra dimensional realisation of the hierarchical wave functions
scenario in which the leptonic FCNC can be efficiently suppressed due to the
strong coupling (CFT) origin of the electron mass.Comment: 23 page
New potentials from Scherk-Schwarz reductions

We study compactifications of eleven-dimensional supergravity on Calabi-Yau
threefolds times a circle, with a duality twist along the circle a la
Scherk-Schwarz. This leads to four-dimensional N=2 gauged supergravity with a
semi-positive definite potential for the scalar fields, which we derive
explicitly. Furthermore, inspired by the orientifold projection in string
theory, we define a truncation to N=1 supergravity. We determine the D-terms,
Kaehler- and superpotentials for these models and study the properties of the
vacua. Finally, we point out a relation to M-theory compactifications on
seven-dimensional manifolds with G2 structure.Comment: 42 pages; v2: typo correcte
Particle Production near an AdS Crunch

We numerically study the dual field theory evolution of five-dimensional
asymptotically anti-de Sitter solutions of supergravity that develop
cosmological singularities. The dual theory is an unstable deformation of the N
= 4 gauge theory on R $\times$ S3, and the big crunch singularity in the bulk
occurs when a boundary scalar field runs to infinity. Consistent quantum
evolution requires one imposes boundary conditions at infinity. Modeling these
by a steep regularization of the scalar potential, we find that when an
initially nearly homogeneous wavepacket rolls down the potential, most of the
potential energy of the initial configuration is converted into gradient energy
during the first oscillation of the field. This indicates there is no
transition from a big crunch to a big bang in the bulk for dual boundary
conditions of this kind.Comment: 20 pages, 6 figure
The Complete Planar S-matrix of N=4 SYM as a Wilson Loop in Twistor
  Space

We propose that the complete planar S-matrix of N=4 super Yang-Mills -
including all N^kMHV partial amplitudes to all loops - is equivalent to the
correlation function of a supersymmetric Wilson loop in twistor space.
Remarkably, the entire classical S-matrix arises from evaluating the
correlation function in the self-dual sector, while the expansion of the
correlation function in powers of the Yang-Mills coupling constant provides the
loop expansion of the amplitudes. We support our proposal with explicit
computations of the n particle NMHV and NNMHV trees, the integrands of the
1-loop MHV and NMHV amplitudes, and the n particle 2-loop MHV amplitude. These
calculations are performed using the twistor action in axial gauge. In this
gauge, the Feynman diagrams of the correlation function are the planar duals of
the usual MHV diagrams for the scattering amplitude. The results are presented
in the form of a sum of products of dual superconformal invariants in
(momentum) twistor space, and agree with the expressions derived in
arXiv:1009.1854 directly from the MHV rules. The twistor space Wilson loop is a
natural supersymmetric generalization of the standard Wilson loop used to
compute MHV amplitudes. We show how the Penrose-Ward transform can be used to
determine a corresponding supersymmetrization on space-time.Comment: 36 pages, 10 figures. Substantial clarification added to section
Natural Supersymmetry at the LHC

If the minimal supersymmetric standard model is the solution to the hierarchy
problem, the scalar top quark (stop) and the Higgsino should weigh around the
electroweak scale such as 200 GeV. A low messenger scale, which results in a
light gravitino, is also suggested to suppress the quantum corrections to the
Higgs mass parameters. Therefore the minimal model for natural supersymmetry is
a system with stop/Higgsino/gravitino whereas other superparticles are heavy.
We study the LHC signatures of the minimal system and discuss the discovery
potential and methods for the mass measurements.Comment: 19 pages, 6 figures, 1 tabl
Topological Lattice Actions

We consider lattice field theories with topological actions, which are
invariant against small deformations of the fields. Some of these actions have
infinite barriers separating different topological sectors. Topological actions
do not have the correct classical continuum limit and they cannot be treated
using perturbation theory, but they still yield the correct quantum continuum
limit. To show this, we present analytic studies of the 1-d O(2) and O(3)
model, as well as Monte Carlo simulations of the 2-d O(3) model using
topological lattice actions. Some topological actions obey and others violate a
lattice Schwarz inequality between the action and the topological charge Q.
Irrespective of this, in the 2-d O(3) model the topological susceptibility
\chi_t = \l< Q^2 >/V is logarithmically divergent in the continuum limit.
Still, at non-zero distance the correlator of the topological charge density
has a finite continuum limit which is consistent with analytic predictions. Our
study shows explicitly that some classically important features of an action
are irrelevant for reaching the correct quantum continuum limit.Comment: 38 pages, 12 figure
Anomaly and a QCD-like phase diagram with massive bosonic baryons

We study a strongly coupled $Z_2$ lattice gauge theory with two flavors of
quarks, invariant under an exact $\mathrm{SU}(2)\times \mathrm{SU}(2) \times
\mathrm{U}_A(1) \times \mathrm{U}_B(1)$ symmetry which is the same as QCD with
two flavors of quarks without an anomaly. The model also contains a coupling
that can be used to break the $\mathrm{U}_A(1)$ symmetry and thus mimic the QCD
anomaly. At low temperatures $T$ and small baryon chemical potential $\mu_B$
the model contains massless pions and massive bosonic baryons similar to QCD
with an even number of colors. In this work we study the $T-\mu_B$ phase
diagram of the model and show that it contains three phases : (1) A chirally
broken phase at low $T$ and $\mu_B$, (2) a chirally symmetric baryon superfluid
phase at low $T$ and high $\mu_B$, and (3) a symmetric phase at high $T$. We
find that the nature of the finite temperature chiral phase transition and in
particular the location of the tricritical point that seperates the first order
line from the second order line is affected significantly by the anomaly.Comment: 22 pages, 16 figures, 5 tables, references adde
Thermal phases of D1-branes on a circle from lattice super Yang-Mills

We report on the results of numerical simulations of 1+1 dimensional SU(N)
Yang-Mills theory with maximal supersymmetry at finite temperature and
compactified on a circle. For large N this system is thought to provide a dual
description of the decoupling limit of N coincident D1-branes on a circle. It
has been proposed that at large N there is a phase transition at strong
coupling related to the Gregory-Laflamme (GL) phase transition in the
holographic gravity dual. In a high temperature limit there was argued to be a
deconfinement transition associated to the spatial Polyakov loop, and it has
been proposed that this is the continuation of the strong coupling GL
transition. Investigating the theory on the lattice for SU(3) and SU(4) and
studying the time and space Polyakov loops we find evidence supporting this. In
particular at strong coupling we see the transition has the parametric
dependence on coupling predicted by gravity. We estimate the GL phase
transition temperature from the lattice data which, interestingly, is not yet
known directly in the gravity dual. Fine tuning in the lattice theory is
avoided by the use of a lattice action with exact supersymmetry.Comment: 21 pages, 8 figures. v2: References added, two figures were modified
  for clarity. v3: Normalisation of lattice coupling corrected by factor of two
  resulting in change of estimate for c_cri
Phase Transitions of Charged Scalars at Finite Temperature and Chemical
  Potential

We calculate the grand canonical partition function at the one-loop level for
scalar quantum electrodynamics at finite temperature and chemical potential. A
classical background charge density with a charge opposite that of the scalars
ensures the neutrality of the system. For low density systems we find evidence
of a first order phase transition. We find upper and lower bounds on the
transition temperature below which the charged scalars form a condensate. A
first order phase transition may have consequences for helium-core white dwarf
stars in which it has been argued that such a condensate of charged helium-4
nuclei could exist.Comment: 20 pages, 3 figures. Version accepted for publication in JHE
Equidistribution Rates, Closed String Amplitudes, and the Riemann
  Hypothesis

We study asymptotic relations connecting unipotent averages of
$Sp(2g,\mathbb{Z})$ automorphic forms to their integrals over the moduli space
of principally polarized abelian varieties. We obtain reformulations of the
Riemann hypothesis as a class of problems concerning the computation of the
equidistribution convergence rate in those asymptotic relations. We discuss
applications of our results to closed string amplitudes. Remarkably, the
Riemann hypothesis can be rephrased in terms of ultraviolet relations occurring
in perturbative closed string theory.Comment: 15 page
Cascade supersymmetry breaking and low-scale gauge mediation

We propose a new class of models with gauge mediated supersymmetry breaking,
the cascade supersymmetry breaking. This class of models is consistent with the
gravitino mass as low as O(1)eV without having suppressed gaugino masses, nor
the Landau pole problems of the gauge coupling constants of the Standard Model
below the scale of the grand unification. In particular, there is no
supersymmetric vacuum in the vicinity of the supersymmetry breaking vacuum even
for such a low gravitino mass. Thus, the model does not have a vacuum stability
problem decaying into supersymmetric vacua.Comment: 27 pages, 3 figure
Born-Infeld electrostatics in the complex plane

The complex method to obtain 2-dimensional Born-Infeld electrostatic
solutions is presented in a renewed form. The solutions are generated by a
holomorphic seed that makes contact with the Coulombian complex potential. The
procedure is exemplified by solving the Born-Infeld multipolar configurations.
Besides, it is shown that the attractive force between two equal but opposite
charges is lower than its Coulombian partner; it decreases up to vanish when
the charges approach each other below a distance ruled by the Born-Infeld
constant.Comment: 15 pages, 4 figure
Gauss-Bonnet Holographic Superconductors

We study holographic superconductors in five dimensional
Einstein-Gauss-Bonnet gravity both numerically and analytically. We find the
critical temperature of the superconductor decreases as backreaction is
increased, although the effect of the Gauss-Bonnet coupling is more subtle: the
critical temperature first decreases then increases as the coupling tends
towards the Chern-Simons value in a backreaction dependent fashion. We compute
the conductivity of the system, finding the energy gap, and show that the
effect of both backreaction and higher curvature is to increase the gap ratio
$\omega_g/T_c$, thus there is no universal relation for these superconductors.Comment: 19 pages, 7 figures, typos corrected, reference adde
Bigger, Better, Faster, More at the LHC

Multijet plus missing energy searches provide universal coverage for theories
that have new colored particles that decay into a dark matter candidate and
jets. These signals appear at the LHC further out on the missing energy tail
than two-to-two scattering indicates. The simplicity of the searches at the LHC
contrasts sharply with the Tevatron where more elaborate searches are necessary
to separate signal from background. The searches presented in this article
effectively distinguish signal from background for any theory where the LSP is
a daughter or granddaughter of the pair-produced colored parent particle
without ever having to consider missing energies less than 400 GeV.Comment: 26 pages, 8 Figures. Minor textual changes, typos fixed and
  references adde
Bi-galileon theory I: motivation and formulation

We introduce bi-galileon theory, the generalisation of the single galileon
model introduced by Nicolis et al. The theory contains two coupled scalar
fields and is described by a Lagrangian that is invariant under Galilean shifts
in those fields. This paper is the first of two, and focuses on the motivation
and formulation of the theory. We show that the boundary effective theory of
the cascading cosmology model corresponds to a bi-galileon theory in the
decoupling limit, and argue that this is to be expected for co-dimension 2
braneworld models exhibiting infra-red modification of gravity. We then
generalise this, by constructing the most general bi-galileon Lagrangian. By
coupling one of the galileons to the energy-momentum tensor, we pitch this as a
modified gravity theory in which the modifications to General Relativity are
encoded in the dynamics of the two galileons. We initiate a study of
phenomenology by looking at maximally symmetric vacua and their stability,
developing elegant geometric techniques that trivially explain why some of the
vacua have to be unstable in certain cases (eg DGP). A detailed study of
phenomenology appears in our companion paper.Comment: 18 pages, JHEP versio
Holographic Superconductors and Higher Curvature Corrections

We study a fully backreacted holographic model of a four-dimensional
superconductor by including a higher curvature interaction in the bulk action.
We study how the critical temperature and the field theory condensate vary in
this model and conclude that positive higher curvature couplings make the
condensation harder. We also compute the conductivity, finding significant
deviations from the conjectured universal frequency gap to critical temperature
ratio.Comment: 16 pages, 6 figures; v2: published version plus one reference adde
Euler-Heisenberg lagrangians and asymptotic analysis in 1+1 QED, part 1:
  Two-loop

We continue an effort to obtain information on the QED perturbation series at
high loop orders, and particularly on the issue of large cancellations inside
gauge invariant classes of graphs, using the example of the l - loop N - photon
amplitudes in the limit of large photons numbers and low photon energies. As
was previously shown, high-order information on these amplitudes can be
obtained from a nonperturbative formula, due to Affleck et al., for the
imaginary part of the QED effective lagrangian in a constant field. The
procedure uses Borel analysis and leads, under some plausible assumptions, to a
number of nontrivial predictions already at the three-loop level. Their direct
verification would require a calculation of this `Euler-Heisenberg lagrangian'
at three-loops, which seems presently out of reach. Motivated by previous work
by Dunne and Krasnansky on Euler-Heisenberg lagrangians in various dimensions,
in the present work we initiate a new line of attack on this problem by
deriving and proving the analogous predictions in the simpler setting of 1+1
dimensional QED. In the first part of this series, we obtain a generalization
of the formula of Affleck et al. to this case, and show that, for both Scalar
and Spinor QED, it correctly predicts the leading asymptotic behaviour of the
weak field expansion coefficients of the two loop Euler-Heisenberg lagrangians.Comment: 28 pages, 1 figures, final published version (minor modifications,
  refs. added
Minimal Gaugomaly Mediation

Mixed anomaly and gauge mediation ("gaugomaly'' mediation) gives a natural
solution to the SUSY flavor problem with a conventional LSP dark matter
candidate. We present a minimal version of gaugomaly mediation where the
messenger masses arise directly from anomaly mediation, automatically
generating a messenger scale of order 50 TeV. We also describe a simple
relaxation mechanism that gives rise to realistic mu and B mu terms. B is
naturally dominated by the anomaly-mediated contribution from top loops, so the
mu/B mu sector only depends on a single new parameter. In the minimal version
of this scenario the full SUSY spectrum is determined by two continuous
parameters (the anomaly- and gauge-mediated SUSY breaking masses) and one
discrete parameter (the number of messengers). We show that these simple models
can give realistic spectra with viable dark matter.Comment: 18 pages, 4 figures; v2: corrected example generating non-holomorphic
  Kahler term
Matrix Norms, BPS Bounds and Marginal Stability in N=8 Supergravity

We study the conditions of marginal stability for two-center extremal black
holes in N-extended supergravity in four dimensions, with particular emphasis
on the N=8 case. This is achieved by exploiting triangle inequalities satisfied
by matrix norms. Using different norms and relative bounds among them, we
establish the existence of marginal stability and split attractor flows both
for BPS and some non-BPS solutions. Our results are in agreement with previous
analysis based on explicit construction of multi-center solutions.Comment: 1+15 pages; v2: some new formulas added and misprints corrected; v3:
  typos fixed, various refinements, Sec. 2.4 rewritten; to appear on JHE
Quantum Strings and the AdS4/CFT3 Interpolating Function

The existence of a nontrivial interpolating function h(\lambda) is one of the
novel features of the new AdS4/CFT3 correspondence involving ABJM theory. At
strong coupling, most of the investigation of semiclassical effects so far has
been for strings in the AdS4 sector. Several cutoff prescriptions have been
proposed, leading to different predictions for the constant term in the
expansion h(\lambda)=\sqrt{\lambda/2} + c + ... . We calculate quantum
corrections for giant magnons, using the algebraic curve, and show by comparing
to the dispersion relation that the same prescriptions lead to the same values
of c in this CP3 sector. We then turn to finite-J effects, where a comparison
with the Luescher F-term correction shows a mismatch for one of the three sum
prescriptions. We also compute some dyonic and higher F-terms for future
comparisons.Comment: 30 pages, 1 figure, 1 table. v2 has minor improvements to the text,
  and extra references. v3 has further textual changes, version to appear in
  JHE
Index Theorem and Overlap Formalism with Naive and Minimally Doubled
  Fermions

We present a theoretical foundation for the Index theorem in naive and
minimally doubled lattice fermions by studying the spectral flow of a Hermitean
version of Dirac operators. We utilize the point splitting method to implement
flavored mass terms, which play an important role in constructing proper
Hermitean operators. We show the spectral flow correctly detects the index of
the would-be zero modes which is determined by gauge field topology. Using the
flavored mass terms, we present new types of overlap fermions from the naive
fermion kernels, with a number of flavors that depends on the choice of the
mass terms. We succeed to obtain a single-flavor naive overlap fermion which
maintains hypercubic symmetry.Comment: 27 pages, 17 figures; references added, version accepted in JHE
Gauge Mediation with Gauge Messengers in SU(5)

The inclusion of gauge messengers in models of gauge mediation allows for
more general predictions that those described by the framework of general gauge
mediation. Motivated by this, we explore some models of gauge mediation with
gauge messengers in SU(5) GUTs. In most previous attempts of building viable
models where gauge messengers play a role in determining the soft terms, squark
and/or slepton masses turned out to be tachyonic. The objective of this paper
is to address this problem and propose two possible solutions, one of which has
a natural realization in the solution of the doublet-triplet problem. Another
interesting result is that in these models the association of SUSY breaking
with the breaking of the GUT group provides a simple mechanism that can explain
why $SU(5)\rightarrow SU(3)\times SU(2) \times U(1)$ is preferred over other
symmetry breaking patterns.Comment: 33 pages, 7 figures, version submitted to jhe