## Recursos de colección

#### Caltech Authors (165.044 recursos)

Repository of works by Caltech published authors.

Group = Walter Burke Institute for Theoretical Physics

1. #### Lepton Flavorful Fifth Force and Depth-dependent Neutrino Matter Interactions

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 $U(1)_{L_e-L_{\mu}, L_{\tau}}$....

2. #### The Conformal Bootstrap at Finite Temperature

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...

3. #### Why Is There Something, Rather Than Nothing?

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.

4. #### Towards Space from Hilbert Space: Finding Lattice Structure in Finite-Dimensional Quantum Systems

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...

5. #### Proof of the Weak Gravity Conjecture from Black Hole Entropy

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...

6. #### Mad-Dog Everettianism: Quantum Mechanics at Its Most Minimal

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...

7. #### Topological Defect Lines and Renormalization Group Flows in Two Dimensions

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.

8. #### Simulations of Core-collapse Supernovae in Spatial Axisymmetry with Full Boltzmann Neutrino Transport

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...

9. #### How Cassini can constrain tidal dissipation in Saturn

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...

10. #### KIC 8164262: a heartbeat star showing tidally induced pulsations with resonant locking

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...

11. #### Why Is There Something, Rather Than Nothing?

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.

12. #### Counting conformal correlators

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.

13. #### Non-Gaussian Enhancements of Galactic Halo Correlations in Quasi-Single Field Inflation

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...

14. #### Non-Gaussian Enhancements of Galactic Halo Correlations in Quasi-Single Field Inflation

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...

15. #### Double-Trace Deformations of Conformal Correlations

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...

16. #### Vector Effective Field Theories from Soft Limits

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.

17. #### Beyond Falsifiability: Normal Science in a Multiverse

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...

18. #### Measurements of the Temperature and E-mode Polarization of the CMB from 500 Square Degrees of SPTpol Data

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,...

19. #### Branches of the Black Hole Wave Function Need Not Contain Firewalls

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...

20. #### 4d N=1/2d Yang-Mills Duality in Holography

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...

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