Condensed Matter Seminar

Theory of free fermions under random projective measurements

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Abstract:  We develop a theory of measurement-induced phase transitions (MIPT) for d-dimensional lattice free fermions subject to random projective measurements of local site occupation numbers. Our analytical approach is based on the Keldysh path-integral formalism and replica trick. In the limit of rare measurements, \gamma << J (where \gamma is measurement rate per site and J is hopping constant), we derive a non-linear sigma model (NLSM) as an effective field theory of the problem.

Exploring New Quantum Horizons

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Abstract: Quantum computers, machines that harness the power of quantum physics and have the potential to outperform their classical counterparts, have recently captured the public's imagination. Amidst the waves of hype and skepticism in the media, what is at the origin of the excitement and what is the real progress of this quest at the frontiers of quantum science and engineering?

Controlling Excitons in 2D Material Heterostructures

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Abstract:
Two dimensional (2D) semiconductors, such as MoSe2 and WSe2, host tightly bound excitons (electron-hole pairs) that interact strongly with light. These monolayer semiconductors can be stacked together to realize heterostructures that exhibit new excitonic effects. In this presentation, I will discuss the optical response of two different 2D semiconductor heterostructures.

A Language Whose Characters are Triangles

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Abstract: One of the most intriguing outcomes of casting our thinking about the world around us in mathematical terms is that phenomena that were thought to be quite distinct are instead revealed as being the “same.” Thinkers as long ago as Pliny the Elder made observations on active matter noting: "It is a peculiarity of the starling to fly in troops, as it were, and then to wheel round in a globular mass like a ball, the central troop acting as a pivot for the rest.’’ In this talk I will introduce field theory and the emergence of the modern theory of active matter as for

Hot band sound

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Abstract: Chaotic lattice models at high temperature are generically expected to exhibit diffusive transport of all local conserved charges. Such diffusive transport is usually associated with overdamped relaxation of the associated currents. We argue that by appropriately tuning the inter-particle interactions, lattice models of chaotic fermions at infinite temperature can be made to cross over from an overdamped regime of diffusion to an underdamped regime of "hot band sound".