Publications (40)
Quantum Complexity and Negative Curvature
Adam R. Brown, Leonard Susskind, Ying Zhao
As time passes, once simple quantum states tend to become more complex. For strongly coupled k-local Hamiltonians, this growth of computational complexity has been conjectured to f…
Quantum Gravity in the Lab: Teleportation by Size and Traversable Wormholes, Part II
Sepehr Nezami, Henry W. Lin, Adam R. Brown +6
In [1] we discussed how quantum gravity may be simulated using quantum devices and gave a specific proposal -- teleportation by size and the phenomenon of size-winding. Here we ela…
Boom and Bust Inflation: a Graceful Exit via Compact Extra Dimensions
Adam R. Brown
A model of inflation is proposed in which compact extra dimensions allow a graceful exit without recourse to flat potentials or super-Planckian field values. Though bubbles of true…
The decay of hot KK space
Adam R. Brown
The non-perturbative instabilities of hot Kaluza-Klein spacetime are investigated. In addition to the known instability of hot space (the nucleation of 4D black holes) and the know…
Enhanced Bishop-Gromov Theorem
Adam R. Brown, Michael H. Freedman
The Bishop-Gromov theorem upperbounds the rate of growth of volume of geodesic balls in a space, in terms of the most negative component of the Ricci curvature. In this paper we pr…
Compactifying de Sitter Naturally Selects a Small Cosmological Constant
Adam R. Brown, Alex Dahlen, Ali Masoumi
We study compactifications of -dimensional de Sitter space with a -form flux down to dimensions. We show that for there are double-exponentially or…
Falling Toward Charged Black Holes
Adam R. Brown, Hrant Gharibyan, Alexandre Streicher +3
The growth of the "size" of operators is an important diagnostic of quantum chaos. In arXiv:1802.01198 [hep-th] it was conjectured that the holographic dual of the size is proporti…
The Complexity Geometry of a Single Qubit
Adam R. Brown, Leonard Susskind
The computational complexity of a quantum state quantifies how hard it is to make. `Complexity geometry', first proposed by Nielsen, is an approach to defining computational comple…
Tensile Strength and the Mining of Black Holes
Adam R. Brown
There are a number of important thought experiments that involve raising and lowering boxes full of radiation in the vicinity of black hole horizons. This paper looks at the limita…
The Python's Lunch: geometric obstructions to decoding Hawking radiation
Adam R. Brown, Hrant Gharibyan, Geoff Penington +1
According to Harlow and Hayden [arXiv:1301.4504] the task of distilling information out of Hawking radiation appears to be computationally hard despite the fact that the quantum st…
Polynomial Equivalence of Complexity Geometries
Adam R. Brown
This paper proves the polynomial equivalence of a broad class of definitions of quantum computational complexity. We study right-invariant metrics on the unitary group -- often cal…
The Thin-Wall Approximation in Vacuum Decay: a Lemma
Adam R. Brown
The 'thin-wall approximation' gives a simple estimate of the decay rate of an unstable quantum field. Unfortunately, the approximation is uncontrolled. In this paper I show that th…
Schwinger pair production at nonzero temperatures or in compact directions
Adam R. Brown
Electric fields may decay by quantum tunneling: as calculated by Schwinger, an electron-positron pair may be summoned from the vacuum. In this paper I calculate the pair-production…
Giant Leaps and Minimal Branes in Multi-Dimensional Flux Landscapes
Adam R. Brown, Alex Dahlen
There is a standard story about decay in multi-dimensional flux landscapes: that from any state, the fastest decay is to take a small step, discharging one flux unit at a time; tha…
Bubbles of Nothing and the Fastest Decay in the Landscape
Adam R. Brown, Alex Dahlen
The rate and manner of vacuum decay are calculated in an explicit flux compactification, including all thick-wall and gravitational effects. For landscapes built of many units of a…
Gemini 1.5: Unlocking multimodal understanding across millions of tokens of context
Gemini Team, Petko Georgiev, Ving Ian Lei +1132
In this report, we introduce the Gemini 1.5 family of models, representing the next generation of highly compute-efficient multimodal models capable of recalling and reasoning over…
Brane tunneling and virtual brane-antibrane pairs
Adam R. Brown
We survey barrier penetration by quantum tunneling for four cases: nonrelativistic point particles, scalar fields, relativistic point particles, and DBI branes. We examine two nove…
Quantum Gravity in the Lab: Teleportation by Size and Traversable Wormholes
Adam R. Brown, Hrant Gharibyan, Stefan Leichenauer +6
With the long-term goal of studying models of quantum gravity in the lab, we propose holographic teleportation protocols that can be readily executed in table-top experiments. Thes…
Complexity, action, and black holes
Adam R. Brown, Daniel A. Roberts, Leonard Susskind +2
Our earlier paper "Complexity Equals Action" conjectured that the quantum computational complexity of a holographic state is given by the classical action of a region in the bulk (…
An Improved Long-Time Bishop-Gromov Theorem Using Shear
Adam R. Brown, Michael H. Freedman
The Bishop-Gromov theorem is a comparison theorem of differential geometry that upperbounds the growth of volume of a geodesic ball in a curved space. For many spaces, this bound i…
A Quantum Complexity Lowerbound from Differential Geometry
Adam R. Brown
The Bishop-Gromov bound -- a cousin of the focusing lemmas that Hawking and Penrose used to prove their black hole singularity theorems -- is a differential geometry result that up…
Gemini 2.5: Pushing the Frontier with Advanced Reasoning, Multimodality, Long Context, and Next Generation Agentic Capabilities
Gheorghe Comanici, Eric Bieber, Mike Schaekermann +3431
In this report, we introduce the Gemini 2.X model family: Gemini 2.5 Pro and Gemini 2.5 Flash, as well as our earlier Gemini 2.0 Flash and Flash-Lite models. Gemini 2.5 Pro is our…
The Smallest Interacting Universe
Modjtaba Shokrian Zini, Adam R. Brown, Michael Freedman
The co-emergence of locality between the Hamiltonian and initial state of the universe is studied in a simple toy model. We hypothesize a fundamental loss functional for the combin…
Universality in long-distance geometry and quantum complexity
Adam R. Brown, Michael H. Freedman, Henry W. Lin +1
In physics, two systems that radically differ at short scales can exhibit strikingly similar macroscopic behaviour: they are part of the same long-distance universality class. Here…
The Second Law of Quantum Complexity
Adam R. Brown, Leonard Susskind
We give arguments for the existence of a thermodynamics of quantum complexity that includes a "Second Law of Complexity". To guide us, we derive a correspondence between the comput…
Thermal derivation of the Coleman-De Luccia tunneling prescription
Adam R. Brown, Erick J. Weinberg
We derive the rate for transitions between de Sitter vacua by treating the field theory on the static patch as a thermal system. This reproduces the Coleman-De Luccia formalism for…
Beyond the Imitation Game: Quantifying and extrapolating the capabilities of language models
Aarohi Srivastava, Abhinav Rastogi, Abhishek Rao +448
Language models demonstrate both quantitative improvement and new qualitative capabilities with increasing scale. Despite their potentially transformative impact, these new capabil…
The Case of the Disappearing Instanton
Adam R. Brown, Alex Dahlen
Instantons are tunneling solutions that connect two vacua, and under a small change in the potential, instantons sometimes disappear. We classify these disappearances as smooth (de…
The evaporation of charged black holes
Adam R. Brown, Luca V. Iliesiu, Geoff Penington +1
Charged particle emission from black holes with sufficiently large charge is exponentially suppressed. As a result, such black holes are driven towards extremality by the emission…
Stability and Spectrum of Compactifications on Product Manifolds
Adam R. Brown, Alex Dahlen
We study the spectrum and perturbative stability of Freund-Rubin compactifications on , where is itself a product of -dimensional Einstein manifo…
Flux Compactifications on
Adam R. Brown, Alex Dahlen, Ali Masoumi
We investigate a simple extra-dimensional model and its four-dimensional vacua. This model has a two-form flux and a positive cosmological constant, and the extra dimensions are co…
Small Steps and Giant Leaps in the Landscape
Adam R. Brown, Alex Dahlen
For landscapes of field theory vacua, we identify an effect that can greatly enhance the decay rates to wildly distant minima--so much so that such transitions may dominate over tr…
Complexity Equals Action
Adam R. Brown, Daniel A. Roberts, Leonard Susskind +2
We conjecture that the quantum complexity of a holographic state is dual to the action of a certain spacetime region that we call a Wheeler-DeWitt patch. We illustrate and test the…
A Wrinkle in Coleman - De Luccia
Adam R. Brown, Saswat Sarangi, Benjamin Shlaer +1
Stringy effects on vacuum transitions are shown to include surprisingly large decay rates through very high potential barriers. This simple, yet counter-intuitive result will drast…
Populating the Whole Landscape
Adam R. Brown, Alex Dahlen
Every de Sitter vacuum can transition to every other de Sitter vacuum despite any obstacle, despite intervening anti-de Sitter sinks, despite not being connected by an instanton. E…
The Channel Capacity of a Relativistic String
Adam R. Brown
I explore the limitations on the capacity of a relativistic channel to transmit power and information that arise because of the finiteness of the transverse speed of light. As a mo…
Playing Pool with : from Bouncing Billiards to Quantum Search
Adam R. Brown
In "Playing Pool with ", Galperin invented an extraordinary method to learn the digits of by counting the collisions of billiard balls. Here I demonstrate an exact isomorp…
Hyperinflation
Adam R. Brown
A model of cosmological inflation is proposed in which field space is a hyperbolic plane. The inflaton never slow-rolls, and instead orbits the bottom of the potential, buoyed by a…
On 'Nothing'
Adam R. Brown, Alex Dahlen
Nothing---the absence of spacetime---can be either an endpoint of tunneling, as in the bubble of nothing, or a starting point for tunneling, as in the quantum creation of a univers…
The Case of the Missing Gates: Complexity of Jackiw-Teitelboim Gravity
Adam R. Brown, Hrant Gharibyan, Henry W. Lin +3
The Jackiw-Teitelboim (JT) model arises from the dimensional reduction of charged black holes. Motivated by the holographic complexity conjecture, we calculate the late-time rate o…