Events During the Week of August 27th through September 3rd, 2023
Sunday, August 27th, 2023
- Academic Calendar
- Graduate School Summer 2023: Doctoral degree deadline
- Time: 11:55 pm - 12:55 am
- Abstract: CONTACT: 262-2433, gsacserv@grad.wisc.edu
Monday, August 28th, 2023
- Academic Calendar
- Graduate School Fall 2023: Fall degree window period begins
- Abstract: Degree candidates must complete all steps: *Important Note: The “Window Period” is the time between the end of one degree period and the beginning of the next. You must have been registered for the previous semester (Fall, Spring, or Summer). If all degree requirements are met by the end of the window period, your degree will be granted for the following semester. However, you will not have to register or pay fees for the next semester. CONTACT: 262-2433, gsacserv@grad.wisc.edu
- Graduate Program Event
- Incoming PhD Orientation
- Time: 9:00 am - 12:30 pm
- Place: 2223 CH
- Speaker: variety of speakers
- Host: Sharon Kahn
Tuesday, August 29th, 2023
- No events scheduled
Wednesday, August 30th, 2023
- Graduate Program Event
- Grad Student lunch/Recess
- Time: 11:30 am - 1:00 pm
- Place: Bascom Hill (rain location: Birge Hall atrium)
- Abstract: ALL physics graduate students (new and continuing) are welcome! Let us know if you plan to join us – RSVP here.
- Host: Sharon Kahn
- Theory Seminar (High Energy/Cosmology)
- Sharpening Weak Gravity Bounds with Charged Superradiance
- Time: 2:30 pm - 3:30 pm
- Place: Chamberlin 5280
- Speaker: Lars Aalsma, Arizona State University
- Abstract: A growing body of evidence suggests that to couple an effective theory to quantum gravity it needs to satisfy the Weak Gravity Conjecture (WGC). Although best understood in flat space, generalizations of the WGC to other spacetimes such as (anti) de Sitter space exist, although this typically leads to undetermined O(1) factors. In this talk, I will give a new perspective on the WGC by relating it to the absence of a black hole instability known as charged superradiance. I will present preliminary results that suggest that this gives a unifying picture of the WGC in flat space, de Sitter and AdS which fixes the O(1) constants.
Thursday, August 31st, 2023
- Graduate Program Event
- Physics Qualifying Exam - Fall 2023 - Classical Mechanics
- Time: 9:00 am - 10:30 am
- Place: 2241 Chamberlin
- Speaker: Sharon Kahn
- R. G. Herb Condensed Matter Seminar
- Integer and fractional Chern insulators in twisted bilayer MoTe2
- Time: 10:00 am
- Place: 5310 Chamberlin Hall
- Speaker: Yihang Zeng, Cornell
- Abstract: Chern insulators, which are the lattice analogs of the quantum Hall states, can potentially manifest high-temperature topological orders at zero magnetic field to enable next-generation topological quantum devices. To date, integer Chern insulators have been experimentally demonstrated in several systems at zero magnetic field, but fractional Chern insulators have been reported only in graphene-based systems under a finite magnetic field. The emergence of semiconductor moiré materials, which support tunable topological flat bands, opens a new opportunity to realize fractional Chern insulators. In this talk, I will present evidence for both integer and fractional Chern insulators at zero magnetic field in small-angle twisted bilayer MoTe2. Combining our newly developed local electronic compressibility measurement and magneto-optical measurement, we find the system is incompressible and spontaneously breaks time reversal symmetry at hole filling factor 1 and 2/3. We show that they are integer and fractional Chern insulators, respectively, from their dispersion in filling factor with applied magnetic field. I will further demonstrate electric-field-tuned topological phase transitions involving the Chern insulators. Our findings pave the way for demonstration of quantized fractional Hall conductance and anyonic excitation and braiding in semiconductor moiré materials.
- Host: Alex Levchenko
- Graduate Program Event
- Physics Qualifying Exam - Fall 2023 - Statistical Mechanics
- Time: 11:30 am - 1:00 pm
- Place: 2241 Chamberlin
- Speaker: Sharon Kahn
Friday, September 1st, 2023
- Graduate Program Event
- Physics Qualifying Exam - Fall 2023 - Electricity & Magnetism
- Time: 9:00 am - 10:30 am
- Place: 2241 Chamberlin
- Speaker: Sharon Kahn
- Graduate Program Event
- Physics Qualifying Exam - Fall 2023 - Quantum Mechanics
- Time: 11:30 am - 1:00 pm
- Place: 2241 Chamberlin
- Speaker: Sharon Kahn