Edward Mazenc
Ph.D. Student in Physics, admitted Autumn 2014
Bio
Broadly speaking, my current work focuses on the idea that spacetime might better be understood as an emergent quantity. The hope is this may help shed light on the many challenges we have faced when trying to understand the nature of spacetime on very small scales. More specifically, and motivated by the holographic principle, I hope to better address the question of how a set of fundamental degrees of freedom might rearrange themselves into the building blocks of spacetime. Inspired by the work of many Stanford colleagues, a large set of tools and concepts once the domain of quantum information theory, such as entanglement entropy, has provided unexpected insights into the possible solutions.
Honors & Awards

NSF Graduate Research Fellow, National Science Foundation (2013)

Alan Barett Prize (for Thesis), MIT (2013)
Education & Certifications

MA.St. (Part III), University of Cambridge, Theoretical Physics (2014)

S.B., Massachusetts Institute of Technology, Physics (2013)
All Publications

Target Space Entanglement Entropy
arXiv.
2019
Abstract
We define a notion of target space entanglement entropy. Rather than partitioning the base space on which the theory is defined, we consider partitions of the target space. This is the physical case of interest for firstquantized theories, such as worldsheet string theory. We associate to each subregion of the target space a suitably chosen subalgebra of observables $\mathcal{A}$. The entanglement entropy is calculated as the entropy of the density matrix restricted to $\mathcal{A}$. As an example, we illustrate our framework by computing spatial entanglement in firstquantized manybody quantum mechanics. The algebra $\mathcal{A}$ is chosen to reproduce the entanglement entropy obtained by embedding the state in the fixed particle subsector of the secondquantized Hilbert space. We then generalize our construction to the quantum fieldtheoretical setting.

A Path Integral Realization of joint JT¯, TJ¯ and TT¯ Flows
arXiv.
2019
Abstract
We recast the joint JT¯, TJ¯ and TT¯ deformations as coupling the original theory to a mixture of topological gravity and gauge theory. This geometrizes the general flow triggered by irrelevant deformations built out of conserved currents and the stressenergy tensor, by means of a path integral kernel. The partition function of the deformed theory satisfies a diffusionlike flow equation similar to that found in the pure TT¯ case. Our proposal passes two stringent tests. Firstly, we recover the classical deformed actions from the kernel, reproducing the known expressions for the free boson and fermion. Secondly, we explicitly compute the torus path integral along the flow and show it localizes to a finitedimensional, oneloop exact integral over base space torus moduli. The dressed energy levels so obtained match exactly onto those previously reported in the literature.

Matrix quantum mechanics from qubits
JOURNAL OF HIGH ENERGY PHYSICS
2017
View details for DOI 10.1007/JHEP01(2017)010
View details for Web of Science ID 000397640300003

Entanglement Entropy in TwoDimensional String Theory
PHYSICAL REVIEW LETTERS
2015; 115 (12)
Abstract
To understand an emergent spacetime is to understand the emergence of locality. Entanglement entropy is a powerful diagnostic of locality, because locality leads to a large amount of short distance entanglement. Twodimensional string theory is among the very simplest instances of an emergent spatial dimension. We compute the entanglement entropy in the largeN matrix quantum mechanics dual to twodimensional string theory in the semiclassical limit of weak string coupling. We isolate a logarithmically large, but finite, contribution that corresponds to the short distance entanglement of the tachyon field in the emergent spacetime. From the spacetime point of view, the entanglement is regulated by a nonperturbative "graininess" of space.
View details for DOI 10.1103/PhysRevLett.115.121602
View details for Web of Science ID 000361316500003
View details for PubMedID 26430982

Primordial bispectrum from multifield inflation with nonminimal couplings
PHYSICAL REVIEW D
2013; 87 (6)
View details for DOI 10.1103/PhysRevD.87.064004
View details for Web of Science ID 000315738400005