Harvard University Department of Physics

Congratulations to Dr. David Morin!

FAS Dean Claudine Gay has approved the promotion of David Morin to Senior Lecturer in Physics...

Artificial Intelligence Accelerates Efforts to Develop Clean, Virtually Limitless Fusion Energy

Artificial intelligence, a branch of computer science that is transforming scientific inquiry and industry, could now speed the development of safe, clean and virtually limitless fusion energy for generating electricity.

UPCOMING EVENTS

Tuesday, May 28th

CMP Special Seminar: Liujun Zou (Harvard)
Start: 02:00pm - End: 03:00pm
- Title: Symmetry-enriched U(1) quantum spin liquids: a formal perspective
  
  Abstract: I will present a classification symmetry fractionalization and anomalies in a 3+1 D U(1) gauge theory enriched by a global symmetry group $G$. We find that, in general, a symmetry-enrichment pattern is specified by 4 pieces of data: $\rho$, a map from $G$ to the duality symmetry group of this U(1) gauge theory which physically encodes how the symmetry permutes the fractional excitations, $\nu\inH^2_{\rho}[G, U_T(1)]$, the symmetry actions on the electric charge, $p\inH^1[G, Z_T]$, indication of certain domain wall decoration with bosonic integer quantum Hall (BIQH) states, and a torsor $n$ over $H^3_{\rho}[G, Z]$, the symmetry actions on the magnetic monopole. However, certain choices of $(\rho, \nu, p, n)$ are not physically realizable, i.e., they are anomalous. We find that there are two levels of anomalies. The first level of anomalies obstruct the fractional excitations being deconfined, thus are referred to as the deconfinement anomaly. States with these anomalies can be realized on the boundary of a 4+1 D long-range entangled state. If a state does not suffer from a deconfinement anomaly, there can still be the second level of anomaly, the more familiar 't Hooft anomaly, which forbids certain types of symmetry fractionalization patterns to be implemented in an on-site fashion. States with these anomalies can be realized on the boundary of a 4+1 D short-range entangled state. We apply these results to some interesting physical examples.
  
  Main reference: Ning, Zou and Cheng, arXiv: 1905.03276.
  Other references: Wang and Senthil, arXiv: 1302.6234.
  Wang and Senthil, arXiv: 1505.03520.
  Zou, Wang and Senthil, arXiv: 1710.00743.
  Zou, arXiv: 1711.03090.
- 02:00pm
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Thursday, May 30th

Commencement
Start: 03:00pm - End: 04:00pm
- 03:00pm
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Wednesday, June 5th

Philippe Bourrianne (MIT)
Start: 06:00pm - End: 07:30pm
- 06:00pm
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Wednesday, June 12th

Kirk Mutafopoulos (Harvard)
Start: 06:00pm - End: 07:30pm
- 06:00pm
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Wednesday, June 19th

Jie Lin (Harvard)
Start: 06:00pm - End: 07:30pm
- 06:00pm
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