P&A Colloquium

On the validity of linear models of electron-lattice coupled systems

BCS theory and its strong-coupling extension have been widely successful in accounting for the properties of conventional superconductors, where phonons mediate pairing. These theoretical frameworks, however, neglect critical physical processes like the formation of competing phases or lattice polarons. This aspect has left several crucial questions in conventional superconductivity unanswered. For example, is there a maximum Tc for conventional superconductors? In this talk, I will discuss recent attempts to answer this question using numerically exact quantum Monte Carlo methods applied to the Holstein hamiltonian. I will show that many parameter regimes considered in the current literature violate the assumptions underlying this canonical toy model. These results remind us that we must be careful when using model hamiltonians to derive general conclusions about materials; however, they also direct us towards a wide-open are of research beyond BCS theory.

Host: Ambrose Seo

Date:
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CP-155
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Tabletop Tests of the Standard Model and Beyond: A Tale of Electron Dipole Moments

The Standard Model of Particle Physics (SM), our most fundamental mathematical description of physics reality, is the great triumph and the great frustration of modern physics.  The triumph is that the SM has survived all laboratory tests.  The frustration is that the SM is not consistent with basic features of the universe.  Tabletop measurements of electron dipole moments provide some of the most stringent tests of the SM and beyond. 

Host: Gardner and Korsch

Date:
Location:
CP 155
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Majorana modes and their identification

We will introduce exotic particles like anyons and Majorana modes and describe
how they obey unfamiliar statistics which are neither like bosons nor like fermions. We will then discuss where one can expect to find such excitations. Finally, we will briefly explain our idea on how to distinguish Majorana modes from impostors.

 

Date:
Location:
CB 102
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Nature Never Deals Off of the Bottom of the Deck…but She Holds All of the Aces: The Joys of Doing Precision Measurement Science

I will talk about, the measurement of little g; Lunar laser ranging (This
year is the 50th anniversary of the Apollo 11 mission to the moon.); and
the measurement of big G, the Newtonian constant of gravitation. I believe
that by extending the reach of our hands & quickening the response of our
eyes, new measurement methods and instrumental capabilities have driven
and implemented much of scientific progress. In my talk I will evidence
the commonality of all precision measurement physics and introduce some
thoughts about doing science. My aim will be for you to carry away from my
talk some new thought, idea, awareness, or perhaps just a saying that you
will want to think about long after I’m gone.

 

Host : Misha Eides

Date:
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Location:
CP 155
Event Series: