Albion Lawrence receives 3-year funding from NASA’s Physical Oceanography program

The ocean is a highly complex, multiscale system, with many types of motions occurring simultaneously. Ocean turbulence between 1km and hundreds of kilometers (the *submesoscale* and *mesoscale*) contains about 90% of the kinetic energy of the ocean, and is crucial for understanding the vertical and horizontal transport of heat, salt, carbon, and microorgamisms; and for understanding the coupling between the ocean and atmosphere. At these scales, internal waves driven by tides and wind also propagate through the ocean and play an important role in mixing such quantities. Characterizing and disentangling these different classes dynamics, and understanding how they interact, is a central problem in physical oceanography. This has become particularly salient with the December 2022 launch of the Surface Water and OceanTopography (SWOT) satellite, which will observe the ocean from space with unprecedented resolution.

Typical studies focus on the kinetic energy as a function of physical scale, (the “power spectrum”), to characterize ocean turbulence. However, this is a fairly blunt instrument and requires more precision than is available. Thus, Joern Callies, Assistant Professor for Environmental Science and Engineering at Caltech and Albion Lawrence, Professor of Physics, intend to use high-order statistical tests, inspired by tools used by observational cosmologists, quantum field theorists, and statistical physicists, to study mesoscale and submesoscale ocean dynamics using satellite observations, direct measurements made in the ocean, and numerical modeling. Their proposal, “Higher-order statistics of geostrophic turbulence and internal waves”, for which Professor Lawrence is the PI and Professor Callies is the Co-PI, was just selected for funding by the Physical Oceanography program at NASA. It was one of nine proposals selected out of 40 in 2022.

Professor Lawrence has been a theoretical high energy physicist for over thirty years, and has only recently begun working in climate-related physics problems. He just co-wrote two papers (arxiv.org, arxiv.org) on black holes and quantum gravity. To further help his move into this new field, he was also awarded a Simons Foundation Pivot Fellowship to spend the 2023-24 academic year embedded in Professor Callies’ group at Caltech. Brandeis’ collegial and interdisciplinary environment had a lot to do with the success and fun Professor Lawrence has had to date. This direction of his research was spurred by his involvement in a large multi-department NSF IGERT grant in “Geometry and Dynamics” that ran from 2011-2018; and got a very important boost from a Provost’s Innovation on “Nonequilbrium Statistical Mechanics of the Ocean and Atmosphere” that Lawrence received in 2019.

Six scientists secure fellowships

One current undergraduate, and five alumni, from the Brandeis Sciences were honored with offers of National Science Foundation Graduate Research Fellowships in 2012. The fellowships, which are awarded based on a national competition, provide three full years of support for Ph.D. research and are highly valued by students and institutions. These students are:

• Samuel McCandlish ’12 (Physics) , a current student who did research with Michael Hagan and Aparna Baskaran, resulting in a paper “Spontaneous segregation of self-propelled particles with different motilities” in Soft Matter (as a junior). He then switched to work with Albion Lawrence for his senior thesis research. Sam will speak about “Bending and Breaking Time Contours: a World Line Approach to Quantum Field Theory” at the Berko Symposium on May 14.  Sam has been offered a couple of other fellowships as well, so he’ll have a nice choice to make. Sam will be heading to Stanford in the fall to continue his studies in theoretical physics.
• Briana Abrahms ’08 (Physics). After graduating from Brandeis, Briana followed her interests in ecological and conversation issues, and  in Africa as a research assistant with the Botswana Predator Conservation Trust, Briana previously described some of her experiences here in “Three Leopards and a Shower“. Briana plans to pursue as Ph.D. in Ecology at UC Davis.
• Sarah Robinson ’07 (Chemistry). Sarah did undergraduate research with Irving Epstein on “Pattern formation in a coupled layer reaction-diffusion system”. After graduating, Sarah spent time with the Peace Corps in Tanzania, returning to study Neurosciene at UCSF.
• Si Hui Pan ’10 (Physics) participated in a summer REU program at Harvard, and continued doing her honors thesis in collaboration with the labs at Harvard. Her award is to study condensed matter physics at MIT.
• Elizabeth Setren ’10 was a Mathematics and Economics double major who worked together with Donald Shepard (Heller School) on the cost of hunger in the US. She has worked as an Assistant Economist at the Federal Reserve Bank of New York and her award is to study Economics at Harvard.
• Michael Ari Cohen ’01 (Psychology) worked as a technology specialist for several years before returning to academia as  PhD student in the Energy and Resources Group at UC Berkeley.

Congratulations to all the winners!

Brandeis in Aspen I: String theory and quantum information

The Aspen Center for Physics is a physics retreat in which groups of researchers in a given field gather for a few weeks during the summer to discuss the latest developments and create the next ones. This May, a record four Brandeis physicists — almost a quarter of the department — visited the Center at the same time, attending two different workshops. This posting is about a workshop attended by string theorists Matthew Headrick and Albion Lawrence (and co-organized by Headrick);  another posting will describe a workshop attended by condensed-matter theorists Aparna Baskaran and Bulbul Chakraborty (a member of the Center’s advisory board).  Entry into Aspen workshops is competitive, so this strong Brandeis representation is remarkable; as always, we punch above our weight.

Headrick and Lawrence attended the workshop Quantum information in quantum gravity and condensed matter physics.  This was a highly interdisciplinary workshop, which brought together specialists in quantum gravity, including Headrick and Lawrence; experts in quantum information theory; and experts in “hard” condensed matter physics (who study material properties for which quantum phenomena play a central role).

Quantum information theorists study how the counterintuitive features of quantum mechanics — such as superpositions of states, entanglement between separated systems, and the collapse of the wave function brought on by measurement — could be exploited to produce remarkable (but so far mostly hypothetical) technologies like teleportation of quantum states, unbreakable encryption, and superfast computation. What does this have to do with gravity? When we try to formulate a consistent quantum-mechanical theory of gravity — which would subsume Einstein’s classical general theory of relativity — the concept of information crops up in numerous and often puzzling ways. For example, Stephen Hawking showed in the 1970s that, on account of quantum effects, black holes emit thermal radiation. Unlike the radiation emitted by conventional hot objects, which is only approximately thermal, pure thermal radiation of the kind that Hawking’s calculation predicted cannot carry information. Many physicists (including Hawking) therefore originally interpreted his result as implying that black holes fundamentally destroy information, challenging a sacred principle of physics. Today, based on advances in string theory, physicists (including Hawking) generally believe that in fact black holes do not destroy the information they contain.  Rather, black holes hide information in very subtle ways, by scrambling, encryption, and perhaps quantum teleportation — in other words, the same kinds of tricks that the quantum information people have been inventing and studying independently at the same time.

Another connection between gravity and information is provided by the so-called “holographic principle”, which also arose in the study of black holes and which has been given a precise realization in the context of string theory. This principle posits that, due to a combination of gravitational and quantum effects, there is a fundamental limit to the amount of information (i.e. the number of bits) that can be stored in a region of space, and furthermore that limit is related to its surface area, not its volume. String theorists, beginning with the seminal work of Juan Maldacena, have uncovered a number of precise implementations of this principle, in which certain quantum theories without gravity are holograms of theories of quantum gravity.  This should provide an avenue for uncovering the “tricks” gravity uses to hide information, a subject Lawrence is active in.  An additional benefit of these implementations is that calculations in the nongravitational theories which seemed prohibitively difficult become fairly simple in the gravitational side; these include  the computation of interesting quantities in quantum information theory, an area in which Headrick has done influential work.

All of these issues and many others were discussed in Aspen. This rather unique workshop was a very fruitful exchange of ideas, with physicists from three fields learning from each other and forging new interdisciplinary collaborations, in a setting where the scenery matched the grandeur of the subject.