Harvard University Department of Physics

Harvard Science Book Talk: Richard Wrangham (Jan 30 @6:00PM)

Photo of Prof. Richard Wrangham and cover of the book "The Goodness Paradox"

In this talk, Prof. Richard Wrangham will discuss his new book, The Goodness Paradox: The Strange Relationship Between Virtue and Violence in Human Evolution

Congratulations to David Morin and Jacob Barandes!

David Morin and Jacob Barandes named Co-Directors of Undergraduate and Graduate Studies, respectively...

UPCOMING EVENTS

Today

CMP Special Seminar: Caroline Gorham (CMU), hosted by David Nelson
Start: 01:00pm - End: 02:00pm
- Title: The Importance of Lie Algebras, Dimensions & Topological Ordering in Understanding the Structure and Thermal Conductivity of Glasses
  
  Abstract: Thermal transport properties of the solid state are tied to the structure that forms from the undercooled atomic liquid. Above approximately 50 K, the thermal conductivity of glasses and crystalline materials show inverse behavior that has remained a matter of inquiry over the past century. This research elucidates the topological origins of solidification of crystalline and non-crystalline solid states, and their thermal transport properties, by adopting a quaternion number to characterize the orientational. In doing so, this topological viewpoint generalizes the fundamental concepts of Bose-Einstein condensation, the Mermin-Wagner theorem and Berezinskii-Kosterlitz-Thouless (BKT) topological ordering transitions from complex to quaternion Lie algebra domains. The Kauzmann point (``ideal glass transition’’) is identified as a self-dual critical point between crystalline and non-crystalline solids, at a critical value of geometrical frustration. This transition is viewed as a higher-dimensional analogue to the superconductor-to-superinsulator quantum phase transition in thin-film Josephson junction arrays (JJAs). Using this topological viewpoint, the inverse thermal transport properties of crystalline and non-crystalline solid states are considered alongside the electrical transport properties of JJAs across the singularity at the superconductor-to-superinsulator transition.
- 01:00pm
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Tuesday, January 22nd

CMP Special Seminar: Zi Yang Meng (IOP, CAS)
Start: 12:00pm - End: 01:00pm
- Title: Revealing fermionic quantum criticality from Monte Carlo simulations
  
  Abstract: Metallic quantum criticality is among the central theme in the understanding of correlated electronic systems, and converging results between analytical and numerical approaches are still under calling. In this talk, I will present recent developments in large-scale quantum Monte Carlo simulations of correlated electron systems. Fresh results on itinerant quantum critical points, i.e. the critical phenomena arising from the strong coupling between Fermi surface and bosonic fluctuations will be discussed. For example, in case of antiferromagnetic quantum critical point, we found that the antiferromagnetic spin fluctuations introduce effective interactions among fermions and the fermions in return render the bare bosonic critical point into a new universality, different from both the bare Ising universality class and the Hertz-Mills-Moriya RPA prediction. At the quantum critical point, a finite anomalous dimension is observed in the bosonic propagator, and fermions at hot spots evolve into a non-Fermi-liquid. In the end, I will also discuss the extension of such numerical setting to the situation of gauge fields coupled to matter fields, which is fundamentally connected to the understanding of deconfined quantum criticality.
- 12:00pm
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Thursday, January 24th

CMP Seminar: Ryan Plestid (McMaster University), hosted by Eugene Demler
Start: 12:00pm - End: 01:00pm
- TBA
- 12:00pm
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Monday, January 28th

Physics Colloquium: Susanne Yelin - Harvard University
Start: 04:15pm - End: 05:15pm
- Controlling Light and Matter Using Cooperative RadiationIt is well known that spontaneous emission, typically assumed to be an independent process for each atom, can be correlated due to the interference of light emitted by different atoms. Over the past five decades, cooperative radiation phenomena such as Dicke's superradiance has been explored in systems ranging from individual atoms to black holes.Recently, such cooperative radiation emerged as a promising method for manipulating light and matter in systems ranging from unordered gases to ordered atomic arrays to two-dimensional semiconductor materials. For instance, cooperative effects can lead to entire manifolds of protected subradiant states whose decay rates approach zero with increasing system size, and to the realization of atomically thin mirrors with exotic properties. Alternatively, controlling the response of the atomic medium by combining spontaneous emission with strong, long-range interactions could be used to control entangled many-body states of atoms. I will discuss several theoretical ideas, ongoing experiments to implement them, as well as potential applications of such effects, including realization of topological optical systems, quantum nonlinear optics, molecule cooling, and quantum information processing.
- 04:15pm
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Wednesday, January 30th

Joint Quantum Seminar: Jelena Vuckovic (Stanford University)
Start: 04:00pm - End: 05:30pm
- Optimized quantum photonics Jelena Vuckovic, Stanford UniversityAt the core of most quantum technologies, including quantum networks and quantum simulators, is the development of homogeneous, long lived qubits with excellent optical interfaces, and the development of high efficiency and robust optical interconnects for such qubits. To achieve this goal, we have been studying color centers in diamond (SiV, SnV) and silicon carbide (VSi in 4H SiC), in combination with novel fabrication techniques, and relying on the powerful and fast photonics inverse design approach that we have developed.Our inverse design approach offers a powerful tool to implement classical and quantum photonic circuits with superior properties, including robustness to errors in fabrication and temperature, compact footprints, novel functionalities, and high efficiencies. We illustrate this with a number of demonstrated devices in silicon, diamond, and silicon carbide, including wavelength and polarization splitters and converters, power splitters, couplers, nonlinear optical isolators, on chip laser driven particle accelerators, and efficient quantum emitter-photon interfaces for color centers in diamond and in SiC. We are also employing this approach to implement a quantum simulator based on color centers in semiconductors.
- 04:00pm
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