Unitarity
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Resolution of Navier-Stokes Smoothness via Universal Boundedness: A Physical Foundation for Global Regularity Open
The Navier-Stokes global regularity problem asks whether smooth initial conditions always lead to smooth solutions. We argue this question reveals a fundamental incompleteness in classical continuum mechanics: the assumption thatphysical p…
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Scattering Amplitudes and the Conservative Hamiltonian for Binary Systems at Third Post-Minkowskian Order Open
We present the amplitude for classical scattering of gravitationally interacting massive scalars at third post-Minkowskian order. Our approach harnesses powerful tools from the modern amplitudes program such as generalized unitarity and th…
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Black hole binary dynamics from the double copy and effective theory Open
A bstract We describe a systematic framework for computing the conservative potential of a compact binary system using modern tools from scattering amplitudes and effective field theory. Our approach combines methods for integration and ma…
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Bootstrapping Mixed Correlators in the 3D Ising Model Open
We study the conformal bootstrap for systems of correlators involving nonidentical operators. The constraints of crossing symmetry and unitarity for such mixed correlators can be phrased in the language of semidefinite programming. We appl…
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General Relativity from Scattering Amplitudes Open
Weoutline the program to apply modern quantum field theory methods to calculate observables in classical general relativity through a truncation to classical terms of the multigraviton, two-body, on-shell scattering amplitudes between mass…
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Implications of unitarity and gauge invariance for simplified dark matter models Open
We show that simplified models used to describe the interactions of dark matter with Standard Model particles do not in general respect gauge invariance and that perturbative unitarity may be violated in large regions of the parameter spac…
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Scattering amplitudes over finite fields and multivariate functional reconstruction Open
Several problems in computer algebra can be efficiently solved by reducing\nthem to calculations over finite fields. In this paper, we describe an\nalgorithm for the reconstruction of multivariate polynomials and rational\nfunctions from t…
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Radiative corrections to neutron and nuclear beta decays revisited Open
The universal radiative corrections common to neutron and superallowed nuclear beta decays (also known as “inner” corrections) are revisited in light of a recent dispersion relation study that found +2.467(22)%, i.e., about 2.4σ larger tha…
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Unitarity and the Holographic S-Matrix Open
The bulk S-Matrix can be given a non-perturbative definition in terms of the flat space limit of AdS/CFT. We show that the unitarity of the S-Matrix, ie the optical theorem, can be derived by studying the behavior of the OPE and the confor…
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Bootstrapping the O(N) archipelago Open
We study 3d CFTs with an O(N) global symmetry using the conformal bootstrap for a system of mixed correlators. Specifically, we consider all nonvanishing scalar four-point functions containing the lowest dimension O(N) vector Φi and the lo…
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GeV-scale thermal WIMPs: Not even slightly ruled out Open
Weakly interacting massive particles (WIMPs) have long reigned as one of the leading classes of dark matter candidates. The observed dark matter abundance can be naturally obtained by freezeout of weak-scale dark matter annihilations in th…
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Two-loop integrand decomposition into master integrals and surface terms Open
Loop amplitudes are conveniently expressed in terms of master integrals whose\ncoefficients carry the process dependent information. Similarly before\nintegration, the loop integrands may be expressed as a linear combination of\npropagator…
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Integration-by-parts reductions from unitarity cuts and algebraic geometry Open
We show that the integration-by-parts reductions of various two-loop integral\ntopologies can be efficiently obtained by applying unitarity cuts to a specific\nset of subgraphs and solving associated polynomial (syzygy) equations.\n
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Radiative classical gravitational observables at $ \\mathcal{O} $(G<sup>3</sup>) from scattering amplitudes Open
We compute classical gravitational observables for the scattering of two spinless black holes in general relativity and N =8 supergravity in the formalism of Kosower, Maybee, and O’Connell (KMOC). We focus on the gravitational impulse with…
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Weak Gravity Conjecture from Unitarity and Causality Open
The weak gravity conjecture states that quantum gravity theories have to contain a charged state with a charge-to-mass ratio bigger than unity. By studying unitarity and causality constraints on higher derivative corrections to the charge-…
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Dispersion relation for hadronic light-by-light scattering: two-pion contributions Open
In our third paper of a series dedicated to a dispersive treatment of the hadronic light-by-light (HLbL) tensor, we derive a partial-wave formulation for two-pion intermediate states in the HLbL contribution to the anomalous magnetic momen…
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Beyond Positivity Bounds and the Fate of Massive Gravity Open
We constrain effective field theories by going beyond the familiar positivity bounds that follow from unitarity, analyticity, and crossing symmetry of the scattering amplitudes. As interesting examples, we discuss the implications of the b…
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Bounding the space of holographic CFTs with chaos Open
In this study, thermal states of quantum systems with many degrees of freedom are subject to a bound on the rate of onset of chaos, including a bound on the Lyapunov exponent, λL ≤ 2π/β. We harness this bound to constrain the space of puta…
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Contributions of axionlike particles to lepton dipole moments Open
We examined contributions of a spin-0 axionlike particle (ALP) to lepton dipole moments, g - 2 and EDMs. Barr-Zee and light-by-light loop effects from a light pseudoscalar ALP are found to be capable of resolving the longstanding muon g - …
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Gravitational Bremsstrahlung from Reverse Unitarity Open
We compute the total radiated momentum carried by gravitational waves during the scattering of two spinless black holes at the lowest order in Newton's constant, O(G^{3}), and all orders in velocity. By analytic continuation into the bound…
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Gravitational effective field theory islands, low-spin dominance, and the four-graviton amplitude Open
We analyze constraints from perturbative unitarity and crossing on the leading contributions of higher-dimension operators to the four-graviton amplitude in four spacetime dimensions, including constraints that follow from distinct helicit…
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The Cosmological Optical Theorem Open
The unitarity of time evolution, or colloquially the conservation of probability, sits at the heart of our descriptions of fundamental interactions via quantum field theory. The implications of unitarity for scattering amplitudes are well …
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Boiling a Unitary Fermi Liquid Open
We study the thermal evolution of a highly spin-imbalanced, homogeneous Fermi gas with unitarity limited interactions, from a Fermi liquid of polarons at low temperatures to a classical Boltzmann gas at high temperatures. Radio-frequency s…
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Analyticity and unitarity for cosmological correlators Open
We study the fundamentals of quantum field theory on a rigid de Sitter space. We show that the perturbative expansion of late-time correlation functions to all orders can be equivalently generated by a non-unitary Lagrangian on a Euclidean…
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The S-matrix bootstrap. Part III: higher dimensional amplitudes Open
A bstract We consider constraints on the S-matrix of any gapped, Lorentz invariant quantum field theory in 3+1 dimensions due to crossing symmetry, analyticity and unitarity. We extremize cubic couplings, quartic couplings and scattering l…
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Black hole collapse in the 1/c expansion Open
We present a first-principles CFT calculation corresponding to the spherical collapse of a shell of matter in three dimensional quantum gravity. In field theory terms, we describe the equilibration process, from early times to thermalizati…
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Ergodic and Nonergodic Dual-Unitary Quantum Circuits with Arbitrary Local Hilbert Space Dimension Open
Dual-unitary quantum circuits can be used to construct 1+1 dimensional lattice models for which dynamical correlations of local observables can be explicitly calculated. We show how to analytically construct classes of dual-unitary circuit…
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Signs of analyticity in single-field inflation Open
The analyticity of response functions and scattering amplitudes implies powerful relations between low-energy observables and the underlying short-distance dynamics. These “IR/UV” relations are rooted in basic physical principles, such as …
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Unitarity, stability, and loops of unstable ghosts Open
We present a new understanding of the unstable ghost-like resonance which\nappears in theories such as quadratic gravity and Lee-Wick type theories.\nQuantum corrections make this resonance unstable, such that it does not appear\nin the as…
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Super-renormalizable or finite Lee–Wick quantum gravity Open
We propose a class of multidimensional higher derivative theories of gravity\nwithout extra real degrees of freedom besides the graviton field. The\npropagator shows up the usual real graviton pole and extra complex conjugates\npoles that …