39 Result(s)
within
Thomas Hartman
Quantum Physics
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Article
Open AccessBlack hole wavefunctions and microcanonical states
We consider the problem of defining a microcanonical thermofield double state at fixed energy and angular momentum from the gravitational path integral. A semiclassical approximation to this state is obtained ...
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Open AccessNull energy constraints on two-dimensional RG flows
We study applications of spectral positivity and the averaged null energy condition (ANEC) to renormalization group (RG) flows in two-dimensional quantum field theory. We find a succinct new proof of the Zamol...
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Open AccessAveraged null energy and the renormalization group
We establish a connection between the averaged null energy condition (ANEC) and the monotonicity of the renormalization group, by studying the light-ray operator ∫ duTuu in quantum field theories that flow betwee...
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Open AccessCoarse graining pure states in AdS/CFT
We construct new Euclidean wormhole solutions in AdSd+1 and discuss their role in UV-complete theories, without ensemble averaging. The geometries are interpreted as overlaps of GHZ-like entangled states, which a...
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Open AccessToward random tensor networks and holographic codes in CFT
In holographic CFTs satisfying eigenstate thermalization, there is a regime where the operator product expansion can be approximated by a random tensor network. The geometry of the tensor network corresponds t...
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Open AccessSemiclassical 3D gravity as an average of large-c CFTs
A two-dimensional CFT dual to a semiclassical theory of gravity in three dimensions must have a large central charge c and a sparse low energy spectrum. This constrains the OPE coefficients and density of states ...
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Open AccessAveraging over moduli in deformed WZW models
WZW models live on a moduli space parameterized by current-current deformations. The moduli space defines an ensemble of conformal field theories, which generically have N abelian conserved currents and central c...
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Open AccessReplica wormholes for an evaporating 2D black hole
Quantum extremal islands reproduce the unitary Page curve of an evaporating black hole. This has been derived by including replica wormholes in the gravitational path integral, but for the transient, evaporati...
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Open AccessFree partition functions and an averaged holographic duality
We study the torus partition functions of free bosonic CFTs in two dimensions. Integrating over Narain moduli defines an ensemble-averaged free CFT. We calculate the averaged partition function and show that i...
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Open AccessHigh-dimensional sphere packing and the modular bootstrap
We carry out a numerical study of the spinless modular bootstrap for conformal field theories with current algebra U(1)c × U(1)c, or equivalently the linear programming bound for sphere packing in 2c dimensions. ...
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Open AccessIslands in cosmology
A quantum extremal island suggests that a region of spacetime is encoded in the quantum state of another system, like the encoding of the black hole interior in Hawking radiation. We study conditions for islan...
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Open AccessIslands in asymptotically flat 2D gravity
The large-N limit of asymptotically flat two-dimensional dilaton gravity coupled to N free matter fields provides a useful toy model for semiclassical black holes and the information paradox. Analyses of the asym...
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Open AccessReplica wormholes and the entropy of Hawking radiation
The information paradox can be realized in anti-de Sitter spacetime joined to a Minkowski region. In this setting, we show that the large discrepancy between the von Neumann entropy as calculated by Hawking an...
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Open AccessDynamical constraints on RG flows and cosmology
Sum rules connecting low-energy observables to high-energy physics are an interesting way to probe the mechanism of inflation and its ultraviolet origin. Unfortunately, such sum rules have proven difficult to ...
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Open AccessSphere packing and quantum gravity
We establish a precise relation between the modular bootstrap, used to con- strain the spectrum of 2D CFTs, and the sphere packing problem in Euclidean geometry. The modular bootstrap bound for chiral algebra ...
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Open AccessFast conformal bootstrap and constraints on 3d gravity
The crossing equations of a conformal field theory can be systematically truncated to a finite, closed system of polynomial equations. In certain cases, solutions of the truncated equations place strict bounds...
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Open AccessShockwaves from the operator product expansion
We clarify and further explore the CFT dual of shockwave geometries in Anti-de Sitter. The shockwave is dual to a CFT state produced by a heavy local operator inserted at a complex point. It can also be create...
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Open AccessHolography at finite cutoff with a T2 deformation
We generalize the T T ¯ ...
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Open AccessThermalization, viscosity and the averaged null energy condition
We explore the implications of the averaged null energy condition for thermal states of relativistic quantum field theories. A key property of such thermal states is the thermalization length. This lengthscale...
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Open AccessConstraints on higher spin CFT2
We derive constraints on two-dimensional conformal field theories with higher spin symmetry due to unitarity, modular invariance, and causality. We focus on CFTs with
