Applied Physics / Physics Colloquium

AP483, Ginzton Lab, & AMO Seminar Series presents Impact of Structural Correlation and Monomer Heterogeneity in the Phase Behavior of Soft Materials and Chromosomal DNA

Topic: 
Impact of Structural Correlation and Monomer Heterogeneity in the Phase Behavior of Soft Materials and Chromosomal DNA
Abstract / Description: 

Polymer self-assembly plays a critical role in a range of soft-material applications and in the organization of chromosomal DNA in living cells. In many cases, the polymer chains are composed of incompatible monomers that are not regularly arranged along the chains. The resulting phase segregation exhibits considerable heterogeneity in the microstructures, and the size scale of these morphologies can be comparable to the statistical correlation that arises from the molecular rigidity of the polymer chains. To establish a predictive understanding of these effects, molecular models must retain sufficient detail to capture molecular elasticity and sequence heterogeneity. This talk highlights efforts to capture these effects using analytical theory and computational modeling. First, we demonstrate the impact of structural rigidity on the phase segregation of copolymer chain in the melt phase, resulting in non-universal phase phenomena due to the interplay of concentration fluctuations and structural correlation. We then demonstrate how these effects impact the phase behavior in statistical random copolymers and in heterogeneous copolymers based on chromosomal DNA properties. With these results, we demonstrate that the spatial segregation of DNA in living cells can be predicted using a heterogeneous copolymer model of microphase segregation.

Date and Time: 
Monday, November 5, 2018 - 4:15pm
Venue: 
Spilker 232

Applied Physics/Physics Colloquium: Quantum mechanical bounds on transport and chaos

Topic: 
Quantum mechanical bounds on transport and chaos
Abstract / Description: 

Transport in strongly quantum systems is challenging to understand. I will describe a recently obtained bound on transport in terms of a characteristic quantum velocity (the Lieb-Robinson velocity) and the local thermalization time. This bound sheds some light on experiments in both condensed matter systems and ultracold atomic gases. At finite temperatures, a more powerful velocity is the so-called butterfly velocity, that is intimately related to quantum chaos. This velocity is still poorly understood; I will present some forthcoming results that constrain the temperature dependence of the butterfly velocity in terms of the underlying quantum scrambling of the system.

Date and Time: 
Monday, October 8, 2018 - 4:15pm
Venue: 
Spilker 232

Applied Physics/Physics Colloquium presents d = 4 N = 2 Field Theory and Physical Mathematics

Topic: 
d = 4 N = 2 Field Theory and Physical Mathematics
Abstract / Description: 

d = 4 N = 2 Field Theory and Physical Mathematics

I will explain the meaning of the two phrases in the title. Much of the talk will be a review of the renowned Seiberg-Witten formulation of the low-energy physics of certain four dimensional supersymmetric interacting quantum field theories. In the latter part of the talk I will briefly describe some of the significant progress that has been made in solving for the so-called BPS sector of the Hilbert space of these theories. Investigations into these physical questions have had a nontrivial impact on mathematics.


 

Aut. Qtr. Colloq. committee: R. Blandford (Chair), A. Kapitulnik, R. Laughlin, L. Senatore
Location: Hewlett Teaching Center, Rm. 200

Date and Time: 
Tuesday, November 27, 2018 - 4:30pm
Venue: 
Hewlett 200

Applied Physics/Physics Colloquium presents Searching for Dark Sectors Under our Noses

Topic: 
Searching for Dark Sectors Under our Noses: Surprising Opportunities at Familiar Mass Scales
Abstract / Description: 

Dark matter is as mysterious as it is ubiquitous. Cosmological evidence raises more questions than it answers about the origin and nature of the most abundant kind of matter in the Universe. Terrestrial experiments searching for answers have focused mainly on the possibility that the constituent of dark matter is a new particle near the Higgs boson mass scale - at the upper limit of the energy ranges ever explored in the laboratory. But recent years have seen a growing interest in the possibility that dark matter is made of particles in a far more pedestrian mass range, comparable to protons or electrons or somewhere in between. Such light dark matter particles could be hiding under our noses, kinematically easy to produce in the laboratory but difficult to detect because they are only produced rarely, through feeble interactions. I will discuss the theoretical underpinnings of sub-GeV dark matter, and the intriguing possibility that dark matter could be our first window into a "dark sector" with new particles and interactions. I will also discuss prospects for new small-scale experiments to explore these ideas, and the exciting prospect that the most strongly motivated parameter space is within reach of next-generation experiments.


 

Aut. Qtr. Colloq. committee: R. Blandford (Chair), A. Kapitulnik, R. Laughlin, L. Senatore
Location: Hewlett Teaching Center, Rm. 200

Date and Time: 
Tuesday, November 13, 2018 - 4:30pm
Venue: 
Hewlett 200

Applied Physics/Physics Colloquium presents High Energy Density Physics – Theory and Experiment in the Realm of the Superlasers

Topic: 
High Energy Density Physics – Theory and Experiment in the Realm of the Superlasers
Abstract / Description: 

High energy density physics may be loosely defined as the study and application of matter and energy above one megabar in pressure – roughly 1 eV/atomic ion at solid density. This regime is characterized by strong ionization, the ubiquity of shocks, fast hydrodynamic instabilities, and the importance of radiation transport in the energy balance of the medium. The microphysics of this regime necessarily deals with the combinatorial complexity of multiply excited atomic ions interacting with radiation. Beyond normal terrestrial experience until recently, the high energy density regime is now the subject of concerted laser and pulsed power experimentation. Examples of applications include stellar astrophysics and inertial confinement fusion. In this colloquium, I will discuss recent theoretical and experimental developments in three significant areas that exemplify the challenges and impact of this physical regime: radiation transfer in local thermal equilibrium and more generally non-local equilibrium, and dynamical viscosity.


 

Aut. Qtr. Colloq. committee: R. Blandford (Chair), A. Kapitulnik, R. Laughlin, L. Senatore
Location: Hewlett Teaching Center, Rm. 200

Date and Time: 
Tuesday, November 6, 2018 - 4:30pm
Venue: 
Hewlett 200

Applied Physics/Physics Colloquium presents The Dynamic Local Universe

Topic: 
The Dynamic Local Universe
Abstract / Description: 

New three-dimensional measurements of the positions and velocities of stars, in particular from the Gaia observatory, have provided unprecedented information on the dynamics of the Milky Way and nearby galaxies. Stellar streams and phase-space structures have been characterized, pointing towards an active recent accretion history by the Milky Way. In this talk, I will discuss how these observations inform hierarchical structure formation, the Milky Way, the Local Group of galaxies, and the nature of dark matter. I will discuss what we can expect from future Gaia data and future astrometric observations.


 

Aut. Qtr. Colloq. committee: R. Blandford (Chair), A. Kapitulnik, R. Laughlin, L. Senatore
Location: Hewlett Teaching Center, Rm. 200

Date and Time: 
Tuesday, October 30, 2018 - 4:30pm
Venue: 
Hewlett 200

Applied Physics/Physics Colloquium: Visiting Newton's Atelier before the Principia, 1679-1684

Topic: 
Visiting Newton's Atelier before the Principia, 1679-1684
Abstract / Description: 

Newton's Principia ignited the Scientific Revolution, but the work-sheets and sketches showing how he composed his masterpiece have been lost. Fortunately, he left behind enough clues to make it possible to give a plausible reconstruction of how he did it. Surprisingly, such a reconstruction has not been attempted before. In the winter of 1679, Robert Hooke initiated a correspondence with Newton outlining the physics of planetary motion. But Hooke was unable to formulate his concepts in mathematical form, and afterward, Newton accomplished this formulation, which allowed him to give a geometrical expression for the passage of time, thus laying the foundations for the Principia. On Dec.10, 1684, four months after a visit of Edmond Halley, Newton sent the first manuscripts for the Principia to the London Royal Society, which he had made "designedly abstruse to be understood only by able Mathematicians". This lack of clarity remains up to the present time. In his talk, I will show, however, that with simply a pencil and a ruler, and without any calculus, good approximations of orbits for central forces can be calculated graphically that also clarify the content of the Principia.


 

Aut. Qtr. Colloq. committee: R. Blandford (Chair), A. Kapitulnik, R. Laughlin, L. Senatore
Location: Hewlett Teaching Center, Rm. 200

Date and Time: 
Tuesday, October 23, 2018 - 4:30pm
Venue: 
Hewlett 200

Applied Physics/Physics Colloquium: Botswana to Bolivia - The Life of an Itinerant Science Educator

Topic: 
Botswana to Bolivia - The Life of an Itinerant Science Educator
Abstract / Description: 

Ranging across Botswana, Bolivia, Nepal, Denmark, The Navajo Nation, and small-town New Jersey, the intricacies of being an international science educator are explored. Does everyone think and communicate as "we" do? How can we maintain our sanity in an increasingly insane world? What are ways that we can best communicate scientific knowledge? These topics are explored in a web of poignant and often humorous anecdotes. The speaker, award-winning educator Phil Deutschle, holds degrees in Physics and Astronomy, is the author of, "The Two-Year Mountain: A Nepal Journey" and "Across African Sand: Journeys of a Witch-Doctor's Son-in-Law," and is the producer of the feature-length documentary, "Searching for Nepal."


 

Aut. Qtr. Colloq. committee: R. Blandford (Chair), A. Kapitulnik, R. Laughlin, L. Senatore
Location: Hewlett Teaching Center, Rm. 200

Date and Time: 
Tuesday, October 16, 2018 - 4:30pm
Venue: 
Hewlett 200

Applied Physics/Physics Colloquium: A High Energy View of the Extreme Universe

Topic: 
A High Energy View of the Extreme Universe
Abstract / Description: 

In the past 10 years, high energy gamma-ray astrophysics has undergone a renaissance. Dramatically improved capabilities from both ground based and space based observatories have combined to unveil dozens of new classes of gamma-ray emitters among the thousands of new sources, and studied each one with unprecedented spatial and spectral capabilities. Continuous monitoring of the high-energy gamma-ray sky has uncovered numerous outbursts from active galaxies, gamma-ray bursts and the discovery of transient sources in our galaxy – some with surprising counterparts. In this talk I will review some of the science highlights from the past decade with an emphasis on the surprises and remaining open questions.


 

Aut. Qtr. Colloq. committee: R. Blandford (Chair), A. Kapitulnik, R. Laughlin, L. Senatore
Location: Hewlett Teaching Center, Rm. 200

Date and Time: 
Tuesday, October 9, 2018 - 4:30pm
Venue: 
Hewlett 200

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