Southeastern regional
mathematical string theory meeting

Next meeting:

Speakers tentatively include Monica Kang (U-Penn), Soumangsu Chakraborty (Ohio State), Diego Garcia-Sepulveda (Chicago), Hao Zhang (VT).

Schedule:

• Friday March 21: Optional informal dinner at Sitar Indian Cuisine at 3630 Durham Chapel Hill Blvd, Durham NC. If you wish to join us, aim to be there by 7:45 - 8 pm, and please let Eric Sharpe know by Thurs March 20 around lunchtime so that he can make a reservation.

• Saturday March 22: All talks will be in Physics room 130.
  • 10:30-11:30: Monica Kang (U-Penn), "Generalized symmetry constraints on deformed 4d (S)CFTs"
    • Abstract: The infrared behavior of asymptotically-free gauge theories in four dimensions demonstrates a wealth of subtle non-perturbative physics. Determining the precise IR dynamics of a given gauge theory is generally challenging due to the dominance of strong coupling effects along the flow into the IR. However, the power of the symmetry approach lies in that it provides consistency constraints that refine the range of possible IR behaviors—and in certain cases, completely determine them. In this talk, I will examine the role of generalized symmetries in four-dimensional N=1 superconformal field theories and the nontrivial constraints they impose on infrared physics. I will begin by classifying 4d N=1 Lagrangian theories with a simple gauge group that possess a nontrivial one-form symmetry and flow to an SCFT. By identifying unbroken discrete zero-form symmetries from the ABJ anomaly, I will show that many of these theories exhibit mixed zero-form/one-form ’t Hooft anomalies. I will then classify the relevant deformations of these SCFTs that preserve these anomalies. Finally, using both the mixed anomalies and the anomalies of discrete zero-form symmetries, I will demonstrate obstructions to these deformations leading to a trivially gapped phase. If time permits, I will highlight powerful extensions of this approach in the context of non-lagrangian theories and on non-supersymmetric deformations.
    • Photos here, here

  • 11:30-1:30: lunch

  • 1:30-2:30: Soumangsu Chakraborty (Ohio State), "Effective AdS_3/CFT_2; Life is simpler without black holes"
    • Abstract: The holographic dual to string theory in $AdS_3 x N$ has always been a fundamental question in high-energy theoretical physics. To this day, we don't know the answer to this question in full generality. In this talk, I'll propose an effective holographic dual to type IIB string theory in $AdS_3 x N$ in the presence of pure NS-NS flux. The dual boundary CFT takes the form of a p-fold symmetric product of (R_\phi \times N) deformed by a \phi-dependent Z_2-twisted marginal operator. I'll explain how an exact worldsheet computation allows us to identify this marginal operator.
      When the radius of AdS_3, R_{ads}, is sub-stringy, the CFT spectrum doesn't contain neither a normalizable vacuum nor the BTZ black hole states. The proposed holographic duality in this case is an exact one. On the other hand, when R_{ads}/l_s >1, the full boundary CFT does have a normalizable vacuum and the BTZ black hole states at high energies. The proposed duality in this case is an effective one and holds only for the perturbative string states in the spectrum. Finally, I'll quote some of the checks that have been performed to test this duality.
    • slides
    • Photos here, here

  • 2:45-3:45: Diego Garcia-Sepulveda (Chicago), "Particle-Soliton Degeneracy in 2D QCD from Spontaneously Broken Non-invertible Symmetry"
    • Abstract: Quantum chromodynamics in two spacetime dimensions admits a finite non-invertible symmetry described mathematically by a fusion category. This symmetry is spontaneously broken at long distances, leading to distinct vacua. When the theory has a mass gap, the spectrum is therefore characterized by particle excitations above a single vacuum and soliton sectors interpolating between vacua. In this talk, I will explain how to use the theory of 2D topological cosets, anyon condensation of 3D TQFTs, and the representation theory of fusion categories to obtain exact results about this spectrum, exhibiting the allowed multiplets. Often, particles and solitons are in the same representation and therefore must have equal masses. Furthermore, the fusion category symmetry frequently implies the existence of certain stable states in the spectrum. The resulting degeneracies are encoded in quiver diagrams where nodes are vacua and arrows are excited states.
    • slides

  • 4:00-4:30: Hao Zhang (VT), "GLSMs of Schubert varieties in Lagrangian Grassmannians"
    • Abstract: We propose a GLSM construction for Schubert varieties in Lagrangian Grassmannians, extending the work of Closset-Khlaif (2023) on ordinary Grassmannians. Starting from the 3d GLSM for Lagrangian Grassmannians, we introduce line defects by coupling 1d GLSMs to the 3d theory. The F-term equations of this coupled system impose constraints that define Schubert varieties. It is well known that the K-theory classes of Schubert varieties provide a natural basis for the (quantum) K-theory ring of the Lagrangian Grassmannian, and correspond to the K-theoretic Schur Q-polynomials. We show that computing the Witten index of the 1d theory recovers these polynomials. Furthermore, dimensional reduction to a 0d/2d system yields a 0d index that matches Schur Q-polynomials, which form a basis for the quantum cohomology ring of Lagrangian Grassmannians.
    • Photos here, here

  • Group photos here, here, here, here

  
  

  Discrimination / diversity:

  The organizers of this meeting are committed to building a diverse, welcoming, and inclusive research environment. We support the non-discrimination statement of the AWM, which can be found here. Any attendee or speaker is welcome to contact any of the organizers directly if he or she feels harassed or excluded.

  If you are an individual with a disability and desire an accommodation, please contact Eric Sharpe (VT office phone 540-381-0185) at least 10 business days prior to the event.

  
  

  Coffee:

  There are several coffee shops located close to the Duke physics department:
  • There are two coffee shops in the Bryan Center.
  • Another coffee shop, ``Twinnies,'' is located in the Fitzpatrick Center.
  • Coffee is served in the LSRC cafeteria.
  • There is a coffee shop in the Perkins Library.

  For visitors to the area:

  • For those flying in, the closest airport is Raleigh-Durham International (RDU).
  • A map of Duke's campus can be found here.
  • We will try to obtain parking passes for the lot beside the physics department building, email Eric Sharpe for such a pass if you will drive in.
  • If you don't have a pass, convenient visitor parking at Duke can often (though not always) be found in the parking deck behind the Bryan Center, off of Science Drive. On rare occasion, that parking deck may be closed or full. In such an event, there is a visitor information center located at the traffic circle on Towerview Road, and the staff there can provide other visitor parking options. (For example, there is a parking deck on Erwin Road, across from the main entrance to the hospital -- but getting from there to the physics department is nontrivial.) Alternatively, see here for a comprehensive list of Duke visitor parking options.
  • For those driving in from out of town, it should be noted that I-40 typically gets jammed with RTP traffic during morning and afternoon rush hours.

  Funding:

  We have (limited) funding available to reimburse students and postdocs, both those speaking and those merely attending who, because of distance travelled, need to spend a night in a hotel, courtesy of NSF grant PHY-2014086.
  IMPORTANT: If you wish to be reimbursed, see here for the paperwork you will need to provide, and also let Eric Sharpe know that you will wish to be reimbursed.
  

  Previous regional meetings:

  For information on previous meetings, see here.
  

  Other upcoming meetings of interest:

  A list of upcoming events in VA can be found here.

  
  
  

  Raleigh-Durham area attractions:

  For those not acquainted with the area, there are a number of things to see. In no particular order, a few include:
  • Overview of Durham attractions
  • Morehead Planetarium in Chapel Hill,
  • There is a small Museum of NC history on the UNC-CH campus.
  • Nasher Museum of Art at Duke University, open late on Thursday evenings,
  • NC Museum of Art in Raleigh,
  • NC Museum of Natural Sciences
  • NC Museum of History
  • Reader's Corner, a used book store on Hillsborough St. in Raleigh,
  • Nice Price Books, another used book store on Hillsborough St. in Raleigh,
  • Other Raleigh events held on the first Friday of every month are listed here,
  • Full Frame Documentary Film Festival, held in April of each year.
  • Events in Chapel Hill are often listed here.