A longstanding goal of violin research has been to establish objectively measurable parameters for violin quality. These would presumably substantiate one of the violin-world’s most passionately held beliefs: Violins made by Stradivari and his contemporaries in 18th Century Italy sound better than any made elsewhere or since. However, a team…

The colloquium talk that was scheduled for Thursday, Feb. 18 has been cancelled.
 

The importance of determining and interpreting the structures of atoms, crystals, and proteins was established long ago. I will discuss current efforts to extend this paradigm to the brain, focusing on new discoveries concerning the structure of the retina gained through 3D electron microscopy, computer vision, and crowdsourcing. I will also…

The eleven year solar activity cycle is a remarkable example of regular behavior emerging from an extremely turbulent system. The jets on Jupiter sit unmoving on a sea of turbulent eddies. Astrophysical phenomena often display organization on spatial and temporal scales much larger than the turbulent processes that drive them. An outstanding…

Living matter obeys the laws of physics, and the principles and methods of theoretical physics ought to find useful application in many areas of biology. This truism is becoming ever more relevant with the rapid growth of the ability of biological experiments to produce comprehensive quantitative data. After a broad survey of the theoretical…

I will describe our recent cosmological results from observations of the Cosmic Microwave Background, including a status report on the recent flight of the Spider experiment, a balloon borne CMB polarimeter. I will also discuss a convergence of observational needs and technological capabilities that provide intriguing opportunities for…

We are fortunate to live at a time when questions about the origin and future of the universe are becoming accessible to scientific inquiry, primarily through observational advances but also through the development of new theoretical ideas. One popular picture is that the very early universe underwent an extraordinary burst of exponential…

Cosmological observations and the dynamics of the Milky Way provide strong evidence for an invisible and dominant mass component that so far reveals its presence only by its gravitational interaction. If the dark matter is made of Weakly Interacting Massive Particles (WIMPs), it can be directly detected via elastic scattering from nuclei in…

I will discuss the discovery of two pentaquark states both decaying into a J/ψ meson and a proton. The decay mode defines the quark content as c cbar, u, u, d, and thus are called charmonium pentaquarks. These exotic structures are found in Λb→J/ψ K- p decays using a full amplitude analysis using 7 and 8 TeV pp collisions from 3/fb of data…

Quantum field theory provides a universal language for very different areas of physics. I will try to demonstrate this by briefly discussing some fundamental problems, both solved and unsolved. The problems will include (if time permits) critical phenomena and conformal bootstrap, quark confinement and gauge/string duality, cosmological…

Recent work has shown that manipulating a quantum system using a periodic drive provides a new means for externally controlling it. Such a periodic drive can give rise to topological states in trivial quantum wells, bulk semiconductors, and even in graphene; and it can also turn a quantum wire into a system which could have Majorana states -…

The bulk of cosmic rays originate in the Milky Way, most likely in supernova explosions. I will discuss the physics aspects of the interaction between charged particles and the environment that are at the very basis of both particle acceleration and propagation throughout the Galaxy and beyond. While we learned a lot from recent cosmic ray and…

The bulk of cosmic rays originate in the Milky Way, most likely in supernova explosions. I will discuss the physics aspects of the interaction between charged particles and the environment that are at the very basis of both particle acceleration and propagation throughout the Galaxy and beyond. While we learned a lot from recent cosmic ray and…

The best rulers are made from light! From gravitational wave interferometers to surface diagnostics, to the definition of the meter, optical interferometry is at the heart of precise measurement. Generally one improves interferometer precision by increasing the light brightness and trying to calm the many technical sources of noise that can…

There has been considerable interest in creating condensed matter systems that host Majorana fermions. This goal is motivated in part by Majorana fermions’ potential use in topological qubits to perform fault-tolerant computation aided by their non-Abelian characteristics. Recently, together with Andrei Bernevig, we have proposed a new…

The Princeton astrophysicist Lyman Spitzer famously figured out how a magnetic field can be used to confine a fully ionized plasma in steady state. His solution, the so-called stellarator, involves a counterintuitive twisting of the field without employing an electric current, and is mathematically related to the Berry phase in quantum…

Over the past several years, our understanding of topological electronic phases of matter has advanced dramatically. A paradigm that has emerged is that insulating electronic states with an energy gap fall into distinct topological classes. Interfaces between different topological phases exhibit gapless conducting states that are protected…

The long-lived noble-gas isotope 81Kr is the ideal tracer for water and ice with ages of 10^5 – 10^6 years, a range beyond the reach of 14C. 81Kr-dating, a concept pursued over the past five decades by numerous laboratories employing a variety of techniques, is finally available to the earth science community at large. This is made possible by…

The long-lived noble-gas isotope 81Kr is the ideal tracer for water and ice with ages of 105 – 106 years, a range beyond the reach of 14C. 81Kr-dating, a concept pursued over the past five decades by numerous laboratories employing a variety of techniques, is finally available to the earth science community at large. This is made possible…

Recently reactor neutrino experiments have made important contributions to the neutrino oscillation. I will introduce the Daya Bay experiment which observed for the first time the neutrino mixing angle θ13 with a statistical significance of 5.2 σ. The concept of the experiment, the detector construction and data analysis will be described. The…