**Thursday, December 14, 2017**

Hamilton Colloquium Series

“Exploring Embryonic Patterning with Colonies of Human Embryonic Stem Cells”

Location: Jadwin Hall, Room A10

Time: 4:00 PM

Speaker(s): Eric Siggia, Rockefeller University**Description:**Embryology at the beginning of the 21st century finds itself in a situation similar to neurobiology; the behavior of the component pieces is understood in some detail, but how they self-assemble to become life is still very hazy. There are hundreds of molecules that enable cell communication and genetics defines their function by classifying aberrant embryos at a suitable intermediate stage of development, which is difficult for mammals and impossible for humans. Embryonic stem cells can be expanded indefinitely and in the context of the embryo give rise to all cells in the body. The colloquium will describe synthetic systems that coax these stem cells to recapitulate aspects of gastrulation, which is the process by which the embryo transforms from a sphere to a cylinder, builds its anterior-posterior and dorsal-ventral axes, and segregates cells into ectoderm (skin and neurons), mesoderm (muscle bones and blood), and endoderm (gut, lungs, pancreas, etc.) lineages.

**Thursday, December 14, 2017**

Raymond and Beverly Sackler Lecture in Astrophysics

“Fast Radio Bursts”

Location: McDonnell A02

Time: 8:00 PM

Speaker(s): Victoria Kaspi, McGill University**Description:**In 2007, astronomers discovered a new mysterious cosmic phenomenon: Fast Radio Bursts. These events consist of short, intense blasts of radio waves arriving from far outside our Milky Way galaxy. Their origin is unknown, however Fast Radio Bursts appear ubiquitous in our Universe, with roughly 1000 arriving every day over the full sky. I will discuss the Fast Radio Burst mystery and what is presently known about it, and describe a revolutionary new radio telescope being built in Canada that will soon enable astronomers worldwide to make major progress in our understanding of the FRB puzzle.

**Friday, December 15, 2017**

High Energy Theory Seminar

“Universality of Quantum Information in Chaotic CFTs”

Location: Bloomberg Lecture Hall

Time: 1:45 PM

Speaker(s): Nima Lashkari, Massachusetts Institute of Technology**Description:**We study the Eigenstate Thermalization Hypothesis (ETH) in chaotic conformal field theories (CFTs) of arbitrary dimensions. Assuming local ETH, we compute the reduced density matrix of a ball-shaped subsystem of finite size in the infinite volume limit when the full system is an energy eigenstate. This reduced density matrix is close in trace distance to a density matrix, to which we refer as the ETH density matrix, that is independent of all the details of an eigenstate except its energy and charges under global symmetries. In two dimensions, the ETH density matrix is universal for all theories with the same value of central charge. We argue that the ETH density matrix is close in trace distance to the reduced density matrix of the (micro)canonical ensemble. We support the argument in higher dimensions by comparing the Von Neumann entropy of the ETH density matrix with the entropy of a black hole in holographic systems in the low temperature limit. Finally, we generalize our analysis to the coherent states with energy density that varies slowly in space, and show that locally such states are well described by the ETH density matrix.

**Monday, January 8, 2018**

PCTS Workshop

“Gravity in the Early Universe”

Location: Jadwin Hall, PCTS Seminar Room, Room 407

Time: 8:30 AM

Note: FREE, but REQUIRED REGISTRATION is limited and available online at http://pcts.princeton.edu/pcts**Description:****Program Organizers:**Anna Ijjas (Columbia), Frans Pretorius (Princeton), Paul J. Steinhardt (Princeton-PCTS)This workshop will focus on modifications of Einstein gravity at high (but sub-Planckian) energy densities that would influence the dynamics and evolutionary history of the early universe. Of particular interest are a variety of recent proposals for avoiding the cosmological singularity by stably violating the null energy condition while remaining in the regime of validity of classical field theories. Understanding these approaches requires the development of new ideas, new analytical tools, and new numerical techniques. The goal is to bring together leading experts in cosmology and general relativity to explore these ideas.

We will have only five speakers and each will be given two 1.5 hour slots, so that there is time for a more pedagogical presentation and lots of time for questions and interaction during and after.

http://wwwphy.princeton.edu/pcts/GravityEarlyUniverse2017/GravityEarlyUniv2017.html

**Tuesday, January 9, 2018**

PCTS Workshop

“Gravity in the Early Universe”

Location: Jadwin Hall, PCTS Seminar Room, Room 407

Time: 8:30 AM

Note: FREE, but REQUIRED REGISTRATION is limited and available online at http://pcts.princeton.edu/pcts**Description:****Program Organizers:**Anna Ijjas (Columbia), Frans Pretorius (Princeton), Paul J. Steinhardt (Princeton-PCTS)This workshop will focus on modifications of Einstein gravity at high (but sub-Planckian) energy densities that would influence the dynamics and evolutionary history of the early universe. Of particular interest are a variety of recent proposals for avoiding the cosmological singularity by stably violating the null energy condition while remaining in the regime of validity of classical field theories. Understanding these approaches requires the development of new ideas, new analytical tools, and new numerical techniques. The goal is to bring together leading experts in cosmology and general relativity to explore these ideas.

We will have only five speakers and each will be given two 1.5 hour slots, so that there is time for a more pedagogical presentation and lots of time for questions and interaction during and after.

http://wwwphy.princeton.edu/pcts/GravityEarlyUniverse2017/GravityEarlyUniv2017.html

**Tuesday, January 9, 2018**

Pheno & Vino Seminar

“TBA”

Location: Jadwin Hal, Room 303

Time: 4:00 PM

Speaker(s): Graham Govanetti, Princeton University

**Wednesday, January 10, 2018**

PCTS Workshop

“Gravity in the Early Universe”

Location: Jadwin Hall, PCTS Seminar Room, Room 407

Time: 8:30 AM

Note: FREE, but REQUIRED REGISTRATION is limited and available online at http://pcts.princeton.edu/pcts**Description:****Program Organizers:**Anna Ijjas (Columbia), Frans Pretorius (Princeton), Paul J. Steinhardt (Princeton-PCTS)This workshop will focus on modifications of Einstein gravity at high (but sub-Planckian) energy densities that would influence the dynamics and evolutionary history of the early universe. Of particular interest are a variety of recent proposals for avoiding the cosmological singularity by stably violating the null energy condition while remaining in the regime of validity of classical field theories. Understanding these approaches requires the development of new ideas, new analytical tools, and new numerical techniques. The goal is to bring together leading experts in cosmology and general relativity to explore these ideas.

We will have only five speakers and each will be given two 1.5 hour slots, so that there is time for a more pedagogical presentation and lots of time for questions and interaction during and after.

http://wwwphy.princeton.edu/pcts/GravityEarlyUniverse2017/GravityEarlyUniv2017.html

**Friday, January 12, 2018**

High Energy Theory Seminar

“TBA”

Location: Bloomberg Lecture Hall

Time: 1:45 PM

Speaker(s): Steve Hsu, Michigan State University

**Tuesday, January 16, 2018**

Pheno & Vino Seminar

“TBA”

Location: Jadwin Hal, Room 303

Time: 4:00 PM

Speaker(s): Kohsaku Tobioka, Stony Brook University

**Monday, March 19, 2018**

High Energy Theory Seminar

“TBA”

Location: Bloomberg Lecture Hall

Time: 2:30 PM

Speaker(s): Guifre Vidal, Perimeter Institute