pinecone/core-2020-05-10-deduplication huggingface dataset:
Variational principle for theories with dissipation from analytic
  continuation

The analytic continuation from the Euclidean domain to real space of the
one-particle irreducible quantum effective action is discussed in the context
of generalized local equilibrium states. Discontinuous terms associated with
dissipative behavior are parametrized in terms of a conveniently defined sign
operator. A generalized variational principle is then formulated, which allows
to obtain causal and real dissipative equations of motion from the analytically
continued quantum effective action. Differential equations derived from the
implications of general covariance determine the space-time evolution of the
temperature and fluid velocity fields and allow for a discussion of entropy
production including a local form of the second law of thermodynamics.Comment: 34 pages, improved discussion of dissipative terms in energy momentum
  tensor, references adde
Extended Symmetries at the Black Hole Horizon

We prove that non-extremal black holes in four-dimensional general relativity
exhibit an infinite-dimensional symmetry in their near horizon region. By
prescribing a physically sensible set of boundary conditions at the horizon, we
derive the algebra of asymptotic Killing vectors, which is shown to be
infinite-dimensional and includes, in particular, two sets of supertranslations
and two mutually commuting copies of the Virasoro algebra. We define the
surface charges associated to the asymptotic diffeomorphisms that preserve the
boundary conditions and discuss the subtleties of this definition, such as the
integrability conditions and the correct definition of the Dirac brackets. When
evaluated on the stationary solutions, the only non-vanishing charges are the
zero-modes. One of them reproduces the Bekenstein-Hawking entropy of Kerr black
holes. We also study the extremal limit, recovering the NHEK geometry. In this
singular case, where the algebra of charges and the integrability conditions
get modified, we find that the computation of the zero-modes correctly
reproduces the black hole entropy. Furthermore, we analyze the case of three
spacetime dimensions, in which the integrability conditions notably simplify
and the field equations can be solved analytically to produce a family of exact
solutions that realize the boundary conditions explicitly. We examine other
features, such as the form of the algebra in the extremal limit and the
relation to other works in the literature.Comment: 24 pages, minor correction
Factorization of Chiral String Amplitudes

We re-examine a closed-string model defined by altering the boundary
conditions for one handedness of two-dimensional propagators in
otherwise-standard string theory. We evaluate the amplitudes using
Kawai-Lewellen-Tye factorization into open-string amplitudes. The only
modification to standard string theory is effectively that the spacetime
Minkowski metric changes overall sign in one open-string factor. This cancels
all but a finite number of states: As found in earlier approaches, with enough
supersymmetry (e.g., type II) the tree amplitudes reproduce those of the
massless truncation of ordinary string theory. However, we now find for the
other cases that additional fields, formerly thought to be auxiliary, describe
new spin-2 states at the two adjacent mass levels (tachyonic and tardyonic).
The tachyon is always a ghost, but can be avoided in the heterotic case.Comment: v2: minor corrections; discussion section modified; more references
  adde
Local subsystems in gauge theory and gravity

We consider the problem of defining localized subsystems in gauge theory and
gravity. Such systems are associated to spacelike hypersurfaces with boundaries
and provide the natural setting for studying entanglement entropy of regions of
space. We present a general formalism to associate a gauge-invariant classical
phase space to a spatial slice with boundary by introducing new degrees of
freedom on the boundary. In Yang-Mills theory the new degrees of freedom are a
choice of gauge on the boundary, transformations of which are generated by the
normal component of the nonabelian electric field. In general relativity the
new degrees of freedom are the location of a codimension-2 surface and a choice
of conformal normal frame. These degrees of freedom transform under a group of
surface symmetries, consisting of diffeomorphisms of the codimension-2
boundary, and position-dependent linear deformations of its normal plane. We
find the observables which generate these symmetries, consisting of the
conformal normal metric and curvature of the normal connection. We discuss the
implications for the problem of defining entanglement entropy in quantum
gravity. Our work suggests that the Bekenstein-Hawking entropy may arise from
the different ways of gluing together two partial Cauchy surfaces at a
cross-section of the horizon.Comment: 46 pages. v2: Error corrected in appendix B, results unchange
Melnikov's method in String Theory

Melnikov's method is an analytical way to show the existence of classical
chaos generated by a Smale horseshoe. It is a powerful technique, though its
applicability is somewhat limited. In this paper, we present a solution of type
IIB supergravity to which Melnikov's method is applicable. This is a brane-wave
type deformation of the AdS$_5\times$S$^5$ background. By employing two
reduction ans\"atze, we study two types of coupled pendulum-oscillator systems.
Then the Melnikov function is computed for each of the systems by following the
standard way of Holmes and Marsden and the existence of chaos is shown
analytically.Comment: 37 pages, 5 figure
Suppression of two-bounce windows in kink-antikink collisions

We consider a class of topological defects in $(1,1)$-dimensions with a
deformed $\phi^4$ kink structure whose stability analysis leads to a
Schr\"odinger-like equation with a zero-mode and at least one vibrational
(shape) mode. We are interested in the dynamics of kink-antikink collisions,
focusing on the structure of two-bounce windows. For small deformation and for
one or two vibrational modes, the observed two-bounce windows are explained by
the standard mechanism of a resonant effect between the first vibrational and
the translational modes. With the increasing of the deformation, the effect of
the appearance of more than one vibrational mode is the gradual disappearance
of the initial two-bounce windows. The total suppression of two-bounce windows
even with the presence of a vibrational mode offers a counterexample from what
expected from the standard mechanism. For even larger deformation, some
two-bounce windows reappear, but with a non-standard structure.Comment: 13 pages, 6 figure
Scattering Amplitude and Bosonization Duality in General Chern-Simons
  Vector Models

We present exact large N calculus of four point function in general
Chern-Simons bosonic and fermionic vector models. Applying the LSZ formula to
the four point function we determine two body scattering amplitudes in these
theories taking a special care for a non-analytic term to achieve unitarity in
the singlet channel. We show that the S-matrix enjoys the bosonization duality,
unusual crossing relation and non-relativistic reduction to Aharonov-Bohm
scattering. We also argue that the S-matrix develops a pole in a certain range
of coupling constants, which disappears in the range where the theory reduces
to Chern-Simons theory interacting with free fermions.Comment: 1+28 pages, 5 figures, v2: minor correction
Ghostbusters in higher derivative supersymmetric theories: who is afraid
  of propagating auxiliary fields?

We present for the first time a ghost-free higher-derivative chiral model
with a propagating auxiliary F-term field (highest component of the chiral
multiplet). We obtain this model by removing a ghost in a higher derivative
chiral model, with Higgsing it in terms of an auxiliary vector superfield.
Depending on the sign of the quadratic derivative term of the chiral
superfield, the model contains two ghost free branches of the parameter
regions. We find that supersymmetry is spontaneously broken in one branch while
it is preserved in the other branch. As a consequence of dynamical F-term
field, a conserved U(1) charge corresponding to the number density of $F$
appears, which can be regarded as a generalization of the R-symmetry.Comment: 15 pages, v2:references adde
Probing CP violation with T2K, NO$\nu$A and DUNE in the presence of
  non-unitarity

The presence of non-unitary neutrino mixing can affect the measurement of the
three-neutrino leptonic Dirac CP phase and hamper efforts to probe CP violation
due to degeneracies of the extra non-unitary CP phase with the standard CP
phase. We study the effect of including non-unitarity on probing CP violation
with the long-baseline experiments NO$\nu$A, T2K and DUNE. We analyze the
effect of non-unitary mixing at the level of oscillation probabilities
associated with the relevant baselines, and present the CP violation
sensitivity for the individual experiments and their combination. Our results
show that there is an improvement in the CP violation sensitivity of the
combination compared to the individual experiments.Comment: 22 pages, 9 figure
Unification of Gauge Couplings in Radiative Neutrino Mass Models

We investigate the possibility of gauge coupling unification in various
radiative neutrino mass models, which generate neutrino masses at one- and/or
two-loop level. Renormalization group running of gauge couplings is performed
analytically and numerically at one- and two-loop order, respectively. We study
three different classes of neutrino mass models: (I) minimal ultraviolet
completions of the dimension-7 $\Delta L=2$ operators which generate neutrino
masses at one- and/or two-loop level without and with dark matter candidates,
(II) models with dark matter which lead to neutrino masses at one-loop level
and (III) models with particles in the adjoint representation of
$\mathrm{SU}(3)$. In class (I), gauge couplings unify in a few models and
adding dark matter amplifies the chances for unification. In class (II), about
a quarter of the models admit gauge coupling unification. In class (III), none
of the models leads to gauge coupling unification. Regarding the scale of
unification, we find values between $10^{14}$ GeV and $10^{16}$ GeV for models
belonging to class (I) without dark matter, whereas models in class (I) with
dark matter as well as models of class (II) prefer values in the range $5 \cdot
10^{10}-5 \cdot 10^{14}$ GeV.Comment: 28 pages, 2 figures. Updated to match journal versio
Two-body non-leptonic heavy-to-heavy decays at NNLO in QCD factorization

We evaluate in the framework of QCD factorization the two-loop vertex
corrections to the decays $\bar{B}_{(s)}\to D_{(s)}^{(\ast)+} \, L^-$ and
$\Lambda_b \to \Lambda_c^+ \, L^-$, where $L$ is a light meson from the set
$\{\pi,\rho,K^{(\ast)},a_1\}$. These decays are paradigms of the QCD
factorization approach since only the colour-allowed tree amplitude contributes
at leading power. Hence they are sensitive to the size of power corrections
once their leading-power perturbative expansion is under control. Here we
compute the two-loop ${\cal O}(\alpha_s^2)$ correction to the leading-power
hard scattering kernels, and give the results for the convoluted kernels almost
completely analytically. Our newly computed contribution amounts to a positive
shift of the magnitude of the tree amplitude by $\sim 2$\%. We then perform an
extensive phenomenological analysis to NNLO in QCD factorization, using the
most recent values for non-perturbative input parameters. Given the fact that
the NNLO perturbative correction and updated values for form factors increase
the theory prediction for branching ratios, while experimental central values
have at the same time decreased, we reanalyze the role and potential size of
power corrections by means of appropriately chosen ratios of decay channels.Comment: 38 pages, 5 tables, 4 figures. v2: Added explicit numbers for
  semi-leptonic rates that enter the factorization test, plus a few more minor
  adjustments. Matches version accepted by JHE
Pion light-by-light contributions to the muon $g-2$

This paper contains some new results on the hadronic light-by-light
contribution (HLbL) to the muon $g-2$. The first part argues that we can expect
large effects from disconnected diagrams in present and future calculations by
lattice QCD of HLbL. The argument is based on the dominance of pseudo-scalar
meson exchange.
  In the second part, we revisit the pion loop HLbL contribution to the muon
anomalous magnetic moment. We study it in the framework of some models studied
earlier, pure pion loop, full VMD and hidden local symmetry for inclusion of
vector mesons. In addition we study possible ways to include the axial-vector
meson. The main part of the work is a detailed study of how the different
momentum regions contribute. We derive a short distance constraint on the
$\gamma^*\gamma^*\to\pi\pi$ amplitude and use this as a constraint on the
models used for the pion loop. As a byproduct we present the general result for
integration using the Gegenbauer polynomial method.Comment: 26 page
Gauge-independent $\overline{MS}$ renormalization in the 2HDM

We present a consistent renormalization scheme for the CP-conserving
Two-Higgs-Doublet Model based on $\overline{MS}$ renormalization of the mixing
angles and the soft-$Z_2$-symmetry-breaking scale $M_{sb}$ in the Higgs sector.
This scheme requires to treat tadpoles fully consistently in all steps of the
calculation in order to provide gauge-independent $S$-matrix elements. We show
how bare physical parameters have to be defined and verify the gauge
independence of physical quantities by explicit calculations in a general
$R_{\xi}$-gauge. The procedure is straightforward and applicable to other
models with extended Higgs sectors. In contrast to the proposed scheme, the
$\overline{MS}$ renormalization of the mixing angles combined with popular
on-shell renormalization schemes gives rise to gauge-dependent results already
at the one-loop level. We present explicit results for electroweak NLO
corrections to selected processes in the appropriately renormalized
Two-Higgs-Doublet Model and in particular discuss their scale dependence.Comment: 52 pages, PDFLaTeX, PDF figures, JHEP version with Eq. (5.23)
  correcte
On 4d rank-one N=3 superconformal field theories

We study the properties of 4d N=3 superconformal field theories whose rank is
one, i.e. those that reduce to a single vector multiplet on their moduli space
of vacua. We find that the moduli space can only be of the form C^3/Z_k for
k=1,2,3,4,6, and that the supersymmetry automatically enhances to N=4 for
k=1,2. In addition, we determine the central charges a and c in terms of k, and
construct the associated 2d chiral algebras, which turn out to be exotic N=2
supersymmetric W-algebras.Comment: 24 page
$O(N)$ model in Euclidean de Sitter space: beyond the leading infrared
  approximation

We consider an $O(N)$ scalar field model with quartic interaction in
$d$-dimensional Euclidean de Sitter space. In order to avoid the problems of
the standard perturbative calculations for light and massless fields, we
generalize to the $O(N)$ theory a systematic method introduced previously for a
single field, which treats the zero modes exactly and the nonzero modes
perturbatively. We compute the two-point functions taking into account not only
the leading infrared contribution, coming from the self-interaction of the zero
modes, but also corrections due to the interaction of the ultraviolet modes.
For the model defined in the corresponding Lorentzian de Sitter spacetime, we
obtain the two-point functions by analytical continuation. We point out that a
partial resummation of the leading secular terms (which necessarily involves
nonzero modes) is required to obtain a decay at large distances for massless
fields. We implement this resummation along with a systematic double expansion
in an effective coupling constant $\sqrt\lambda$ and in 1/N. We explicitly
perform the calculation up to the next-to-next-to-leading order in
$\sqrt\lambda$ and up to next-to-leading order in 1/N. The results reduce to
those known in the leading infrared approximation. We also show that they
coincide with the ones obtained directly in Lorentzian de Sitter spacetime in
the large N limit, provided the same renormalization scheme is used.Comment: 31 pages, 5 figures. Minor changes. Published versio
A Natural origin for the LHCb anomalies

The anomalies recently found by the LHCb collaboration in $B$-meson decays
seem to point towards the existence of new physics coupled non-universally to
muons and electrons. We show that a beyond-the-Standard-Model dynamics with
these features naturally arises in models with a warped extra-dimension that
aim to solve the electroweak Hierarchy Problem. The attractiveness of our
set-up is the fact that the dynamics responsible for generating the flavor
anomalies is automatically present, being provided by the massive Kaluza--Klein
excitations of the electroweak gauge bosons. The flavor anomalies can be easily
reproduced by assuming that the bottom and muon fields have a sizable amount of
compositeness, while the electron is almost elementary. Interestingly enough,
this framework correlates the flavor anomalies to a pattern of corrections in
the electroweak observables and in flavor-changing processes. In particular the
deviations in the bottom and muon couplings to the $Z$-boson and in $\Delta F =
2$ flavor-changing observables are predicted to be close to the present
experimental bounds, and thus potentially testable in near-future experiments.Comment: 33 pages, 14 figures, 1 table. References adde
Challenges for D-brane large-field inflation with stabilizer fields

We study possible string theory compactifications which, in the low-energy
limit, describe chaotic inflation with a stabilizer field. We first analyze
type IIA setups where the inflationary potential arises from a D6-brane
wrapping an internal three-cycle, and where the stabilizer field is either an
open-string or bulk K\"ahler modulus. We find that after integrating out the
relevant closed-string moduli consistently, tachyonic directions arise during
inflation which cannot be lifted. This is ultimately due to the shift
symmetries of the type IIA K\"ahler potential at large compactification volume.
This motivates us to search for stabilizer candidates in the complex structure
sector of type IIB orientifolds, since these fields couple to D7-brane Wilson
lines and their shift symmetries are generically broken away from the large
complex structure limit. However, we find that in these setups the challenge is
to obtain the necessary hierarchy between the inflationary and Kaluza-Klein
scales.Comment: 26 pages, typos corrected and comments added. Published versio
M5-branes on S^2 x M_4: Nahm's Equations and 4d Topological Sigma-models

We study the 6d N=(0,2) superconformal field theory, which describes multiple
M5-branes, on the product space S^2 x M_4, and suggest a correspondence between
a 2d N=(0,2) half-twisted gauge theory on S^2 and a topological sigma-model on
the four-manifold M_4. To set up this correspondence, we determine in this
paper the dimensional reduction of the 6d N=(0,2) theory on a two-sphere and
derive that the four-dimensional theory is a sigma-model into the moduli space
of solutions to Nahm's equations, or equivalently the moduli space of
k-centered SU(2) monopoles, where k is the number of M5-branes. We proceed in
three steps: we reduce the 6d abelian theory to a 5d Super-Yang-Mills theory on
I x M_4, with I an interval, then non-abelianize the 5d theory and finally
reduce this to 4d. In the special case, when M_4 is a Hyper-Kahler manifold, we
show that the dimensional reduction gives rise to a topological sigma-model
based on tri-holomorphic maps. Deriving the theory on a general M_4 requires
knowledge of the metric of the target space. For k=2 the target space is the
Atiyah-Hitchin manifold and we twist the theory to obtain a topological
sigma-model, which has both scalar fields and self-dual two-forms.Comment: 78 pages, 2 figure
Non-chiral 2d CFT with integer energy levels

The partition function of 2d conformal field theory is a modular invariant
function. It is known that the partition function of a holomorphic CFT whose
central charge is a multiple of 24 is a polynomial in the Klein function. In
this paper, by using the medium temperature expansion we show that every
modular invariant partition function can be mapped to a holomorphic partition
function whose structure can be determined similarly. We use this map to study
partition function of CFTs with half-integer left and right conformal weights.
We show that the corresponding left and right central charges are necessarily
multiples of 4. Furthermore, the degree of degeneracy of high-energy levels can
be uniquely determined in terms of the degeneracy in the low energy states.Comment: v2: 19 pages, few footnotes and a reference added, to appear in JHE
Negative magnetoresistivity in holography

Negative magnetoresistivity is a special magnetotransport property associated
with chiral anomaly in four dimensional chiral anomalous systems, which refers
to the transport behavior that the DC longitudinal magnetoresistivity decreases
with increasing magnetic field. We calculate the longitudinal
magnetoconductivity in the presence of backreactions of the magnetic field to
gravity in holographic zero charge and axial charge density systems with and
without axial charge dissipation. In the absence of axial charge dissipation,
we find that the quantum critical conductivity grows with increasing magnetic
field when the backreaction strength is larger than a critical value, in
contrast to the monotonically decreasing behavior of quantum critical
conductivity in the probe limit. With axial charge dissipation, we find the
negative magnetoresistivity behavior. The DC longitudinal magnetoconductivity
scales as $B$ in the large magnetic field limit, which deviates from the exact
$B^2$ scaling of the probe limit result. In both cases, the small frequency
longitudinal magnetoconductivity still agrees with the formula obtained from
the hydrodynamic linear response theory, even in the large magnetic field
limit.Comment: 33 pages, 13 figures; v2, minor change, version to appear in JHE
Gravitational Tension, Spacetime Pressure and Black Hole Volume

We study the first law of black hole thermodynamics in the presence of
surrounding gravitational fields and argue that variations of these fields are
naturally incorporated in the first law by defining gravitational tension or
gravitational binding energy. We demonstrate that this notion can also be
applied in Anti-de Sitter spacetime, in which the surrounding gravitational
field is sourced by a cosmological fluid, therefore showing that spacetime
volume and gravitational tension encode the same physics as spacetime pressure
and black hole volume. We furthermore show that it is possible to introduce a
definition of spacetime pressure and black hole volume for any spacetime with
characteristic length scales which does not necessarily require a cosmological
constant sourcing Einstein equations. However, we show that black hole volume
is non-universal in the flat spacetime limit, questioning its significance. We
illustrate these ideas by studying the resulting black hole volume of
Kaluza-Klein black holes and of a toy model for a black hole binary system in
five spacetime dimensions (the black saturn solution) as well as of several
novel perturbative black hole solutions. These include the higher-dimensional
Kerr-Newman solution in Anti-de Sitter spacetime as well as other black holes
in plane wave and Lifshitz spacetimes.Comment: v3: 42pp, improved discussion in section 6, to be published in JHE