Recursos de colección
Caltech Authors (165.044 recursos)
Repository of works by Caltech published authors.
Group = Walter Burke Institute for Theoretical Physics
Repository of works by Caltech published authors.
Group = Walter Burke Institute for Theoretical Physics
Wise, Mark B.; Zhang, Yue
We consider a fifth force to be an interaction that couples to matter with a
strength that grows with the number of atoms. In addition to competing with the
strength of gravity a fifth force can give rise to violations of the
equivalence principle. Current long range constraints on the strength and range
of fifth forces are very impressive. Amongst possible fifth forces are those
that couple to lepton flavorful charges $L_e-L_{\mu}$ or $L_e-L_{\tau}$. They
have the property that their range and strength are also constrained by
neutrino interactions with matter. In this brief note we review the existing
constraints on the allowed parameter space in gauged $U(1)_{L_e-L_{\mu},
L_{\tau}}$....
Iliesiu, Luca; Koloğlu, Murat; Mahajan, Raghu; Perlmutter, Eric; Simmons-Duffin, David
We initiate an approach to constraining conformal field theory (CFT) data at
finite temperature using methods inspired by the conformal bootstrap for vacuum
correlation functions. We focus on thermal one- and two-point functions of
local operators on the plane. The KMS condition for thermal two-point functions
is cast as a crossing equation. By studying the analyticity properties of
thermal two-point functions, we derive a "thermal inversion formula" whose
output is the set of thermal one-point functions for all operators appearing in
a given OPE. This involves identifying a kinematic regime which is the analog
of the Regge regime for four-point functions. We demonstrate the effectiveness
of the inversion formula...
Carroll, Sean M.
It seems natural to ask why the universe exists at all. Modern physics
suggests that the universe can exist all by itself as a self-contained system,
without anything external to create or sustain it. But there might not be an
absolute answer to why it exists. I argue that any attempt to account for the
existence of something rather than nothing must ultimately bottom out in a set
of brute facts; the universe simply is, without ultimate cause or explanation.
Pollack, Jason; Singh, Ashmeet
Field theories place one or more degrees of freedom at every point in space.
Hilbert spaces describing quantum field theories, or their finite-dimensional
discretizations on lattices, therefore have large amounts of structure: they
are isomorphic to the tensor product of a smaller Hilbert space for each
lattice site or point in space. Local field theories respecting this structure
have interactions which preferentially couple nearby points. The emergence of
classicality through decoherence relies on this framework of tensor-product
decomposition and local interactions. We explore the emergence of such lattice
structure from Hilbert-space considerations alone. We point out that the vast
majority of finite-dimensional Hilbert spaces cannot be isomorphic to the
tensor...
Cheung, Clifford; Liu, Junyu; Remmen, Grant N.
Appending new microstates to a system inevitably increases the entropy
associated with a fixed macroscopic configuration. If those extra degrees of
freedom are short-distance modes, then their long-distance effects are encoded
by higher-dimension operators. In the context of Einstein-Maxwell theory, these
corrections modify the entropy of a charged black hole through the Wald entropy
formula. Requiring that the shift in black hole entropy be strictly positive at
fixed mass and charge then mandates new positivity conditions on the
coefficients of higher-dimension operators. These bounds imply that the
coefficient of the Riemann-squared term is positive and that the charge-to-mass
ratio of an extremal black hole asymptotes to unity from above...
Carroll, Sean M.; Singh, Ashmeet
To the best of our current understanding, quantum mechanics is part of the
most fundamental picture of the universe. It is natural to ask how pure and
minimal this fundamental quantum description can be. The simplest quantum
ontology is that of the Everett or Many-Worlds interpretation, based on a
vector in Hilbert space and a Hamiltonian. Typically one also relies on some
classical structure, such as space and local configuration variables within it,
which then gets promoted to an algebra of preferred observables. We argue that
even such an algebra is unnecessary, and the most basic description of the
world is given by the spectrum of the Hamiltonian...
Chang, Chi-Ming; Lin, Ying-Hsuan; Shao, Shu-Heng; Wang, Yifan; Yin, Xi
We consider topological defect lines (TDLs) in two-dimensional conformal
field theories. Generalizing and encompassing both global symmetries and
Verlinde lines, TDLs together with their attached defect operators provide
models of fusion categories without braiding. We study the crossing relations
of TDLs, discuss their relation to the 't Hooft anomaly, and use them to
constrain renormalization group flows to either conformal critical points or
topological quantum field theories (TQFTs). We show that if certain
non-invertible TDLs are preserved along a RG flow, then the vacuum cannot be a
non-degenerate gapped state. For various massive flows, we determine the
infrared TQFTs completely from the consideration of TDLs together with modular
invariance.
Nagakura, Hiroki; Iwakami, Wakana; Furusawa, Shun; Okawa, Hirotada; Harada, Akira; Sumiyoshi, Kohsuke; Yamada, Shoichi; Matsufuru, Hideo; Imakura, Akira
We present the first results of our spatially axisymmetric core-collapse supernova simulations with full Boltzmann neutrino transport, which amount to a time-dependent five-dimensional (two in space and three in momentum space) problem. Special relativistic effects are fully taken into account with a two-energy-grid technique. We performed two simulations for a progenitor of 11.2 M☉, employing different nuclear equations of state (EOSs): Lattimer and Swesty's EOS with the incompressibility of K = 220 MeV (LS EOS) and Furusawa's EOS based on the relativistic mean field theory with the TM1 parameter set (FS EOS). In the LS EOS, the shock wave reaches...
Luan, Jing; Fuller, Jim; Quataert, Eliot
Tidal dissipation inside giant planets is important for the orbital evolution of their natural satellites. It is conventionally treated by parametrized equilibrium tidal theory, in which the tidal torque declines rapidly with distance, and orbital expansion was faster in the past. However, some Saturnian satellites are currently migrating outward faster than predicted by equilibrium tidal theory. Resonance locking between satellites and internal oscillations of Saturn naturally matches the observed migration rates. Here, we show that the resonance locking theory predicts dynamical tidal perturbations to Saturn's gravitational field in addition to those produced by equilibrium tidal bulges. We show that these...
Hambleton, K.; Fuller, J.; Thompson, S.; Prša, A.; Kurtz, D. W.; Shporer, A.; Isaacson, H.; Howard, A. W.; Endl, M.; Cochran, W.; Murphy, S. J.
We present the analysis of KIC 8164262, a heartbeat star with a high-amplitude (∼1 mmag), tidally resonant pulsation (a mode in resonance with the orbit) at 229 times the orbital frequency and a plethora of tidally induced g-mode pulsations (modes excited by the orbit). The analysis combines Kepler light curves with follow-up spectroscopic data from the Keck telescope, KPNO (Kitt Peak National Observatory) 4-m Mayall telescope and the 2.7-m telescope at the McDonald observatory. We apply the binary modelling software, PHOEBE, to the Kepler light curve and radial velocity data to determine a detailed binary star model that includes the prominent pulsation...
Carroll, Sean M.
It seems natural to ask why the universe exists at all. Modern physics
suggests that the universe can exist all by itself as a self-contained system,
without anything external to create or sustain it. But there might not be an
absolute answer to why it exists. I argue that any attempt to account for the
existence of something rather than nothing must ultimately bottom out in a set
of brute facts; the universe simply is, without ultimate cause or explanation.
Kravchuk, Petr; Simmons-Duffin, David
We introduce simple group-theoretic techniques for classifying conformallyinvariant tensor structures. With them, we classify tensor structures of general n-point functions of non-conserved operators, and n ≥ 4-point functions of general conserved currents, with or without permutation symmetries, and in any spacetime dimension d. Our techniques are useful for bootstrap applications. The rules we derive simultaneously count tensor structures for flat-space scattering amplitudes in d + 1 dimensions.
An, Haipeng; McAneny, Michael; Ridgway, Alexander K.; Wise, Mark B.
We consider a quasi-single field inflation model in which the inflaton interacts with a massive scalar field called the isocurvaton. Due to the breaking of time translational invariance by the inflaton background, these interactions induce kinetic mixing between the inflaton and isocurvaton, which is parameterized by a constant μ. We derive analytic formulae for the curvature perturbation two-, three-, four-, five-, and six-point functions explicitly in terms of the external wave-vectors in the limit where μ and the mass of the isocurvaton m are both much smaller than H. In previous work, it has been noted that when m/H and...
An, Haipeng; McAneny, Michael; Ridgway, Alexander K.; Wise, Mark B.
We consider a quasi-single field inflation model in which the inflaton interacts with a massive scalar field called the isocurvaton. Due to the breaking of time translational invariance by the inflaton background, these interactions induce kinetic mixing between the inflaton and isocurvaton, which is parameterized by a constant μ. We derive analytic formulae for the curvature perturbation two-, three-, four-, five-, and six-point functions explicitly in terms of the external wave-vectors in the limit where μ and the mass of the isocurvaton m are both much smaller than H. In previous work, it has been noted that when m/H and...
Giombi, Simone; Kirilin, Vladimir; Perlmutter, Eric
Large N conformal field theories often admit unitary renormalization group flows triggered by double-trace deformations. We compute the change in scalar four-point functions under double-trace flow, to leading order in 1/N. This has a simple dual in AdS, where the flow is implemented by a change of boundary conditions, and provides a physical interpretation of single-valued conformal partial waves. We extract the change in the conformal dimensions and three-point coefficients of infinite families of double-trace composite operators. Some of these quantities are found to be sign-definite under double-trace flow. As an application, we derive anomalous dimensions of spinning double-trace operators...
Cheung, Clifford; Kampf, Karol; Novotny, Jiri; Shen, Chia-Hsien; Trnka, Jaroslav; Wen, Congkao
We present a bottom-up construction of vector effective field theories using
the infrared structure of scattering amplitudes. Our results employ two
distinct probes of soft kinematics: multiple soft limits and single soft limits
after dimensional reduction, applicable in four and general dimensions,
respectively. Both approaches uniquely specify the Born-Infeld (BI) model as
the only theory of vectors completely fixed by certain infrared conditions
which generalize the Adler zero for pions. These soft properties imply new
recursion relations for on-shell scattering amplitudes in BI theory and suggest
the existence of a wider class of vector effective field theories.
Carroll, Sean M.
Cosmological models that invoke a multiverse - a collection of unobservable
regions of space where conditions are very different from the region around us
- are controversial, on the grounds that unobservable phenomena shouldn't play
a crucial role in legitimate scientific theories. I argue that the way we
evaluate multiverse models is precisely the same as the way we evaluate any
other models, on the basis of abduction, Bayesian inference, and empirical
success. There is no scientifically respectable way to do cosmology without
taking into account different possibilities for what the universe might be like
outside our horizon. Multiverse theories are utterly conventionally scientific,
even if evaluating them can...
Henning, J. W.; Moran, C. Corbett; Crites, A. T.; Padin, S.
We present measurements of the E-mode polarization angular auto-power spectrum (EE) and temperature–E-mode cross-power spectrum (TE) of the cosmic microwave background (CMB) using 150 GHz data from three seasons of SPTpol observations. We report the power spectra over the spherical harmonic multipole range 50 < ℓ ⩽ 8000 and detect nine acoustic peaks in the EE spectrum with high signal-to-noise ratio. These measurements are the most sensitive to date of the EE and TE power spectra at ℓ > 1050 and ℓ > 1475, respectively. The observations cover 500 deg^2, a fivefold increase in area compared to previous SPTpol analyses,...
Bao, Ning; Carroll, Sean M.; Chatwin-Davies, Aidan; Pollack, Jason; Remmen, Grant N.
We discuss the branching structure of the quantum-gravitational wave function
that describes the evaporation of a black hole. A global wave function that
initially describes a classical Schwarzschild geometry is continually decohered
into distinct semiclassical branches by the emission of Hawking radiation. The
laws of quantum mechanics dictate that the wave function evolves unitarily, but
this unitary evolution is only manifest when considering the global description
of the wave function: it is not implemented by time evolution on a single
semiclassical branch. Conversely, geometric notions like the position or
smoothness of a horizon only make sense on the level of individual branches. We
consider the implications of this picture...
Fluder, Martin
We study the supergravity dual of four-dimensional N=1 superconformal field theories arising from wrapping M5-branes on a K\"ahler two-cycle inside a Calabi-Yau threefold. We derive an effective three-dimensional theory living on the cobordism between the infrared and ultraviolet Riemann surfaces, describing the renormalization group flows between AdS_7 and AdS_5 as well as between different AdS_5 fixed points. The realization of this system as an effective theory is convenient to make connections to known theories, and we show that upon imposing (physical) infrared boundary conditions, the effective three-dimensional theory further reduces to two-dimensional SU(2) Yang-Mills theory on the Riemann surface, thus...