Talks

The VERITAS Imaging Atmospheric Cherenkov Telescope array was augmented in 2019 with high-speed focal plane electronics to allow VERITAS for Stellar Intensity Interferometry (VSII) observations. Since December 2019, VSII has been used to measure angular diameters of bright (OBA) stars at an effective wavelength of 416 nm. VSII observations have also served as a testbed to explore hardware and analysis improvements to advance the instrument's sensitivity. VSII has performed more than 730 hours of moonlit observations on 56 bright stars and binary systems ($ -1.46 < m_V < 4.22$). This talk will describe the VSII observatory, highlight selected observations made by the VSII observatory, and describe ongoing improvements in detector instrumentation and analysis.

The renaissance in stellar intensity interferometry has resulted in two main types of telescope arrays: those using large "light bucket" telescopes and photomultiplier tubes, such as CTA, VERITAS, MAGIC, and others, and those that instead use smaller, more traditional astronomical telescopes with high-grade optics, such as the systems at the Cote d'Azur and Asiago Observatories. To detect and timestamp photons, these latter systems have used single-photon avalanche diode (SPAD) detectors. This talk will focus on the latter type of instrument, which is also being pursued at Southern Connecticut State University. The current status of our instrument, the Southern Connecticut Stellar Interferometer (SCSI), will be reviewed, and prospects for improved sensitivity will be discussed. Principal among these is the use of SPAD arrays, which are increasingly available, to record different wavelengths simultaneously. If a sufficient number of channels can be employed, this type of intensity interferometer can reach much fainter magnitudes than currently possible. The talk will also briefly discuss work toward wireless intensity interferometry with SCSI, which will make larger baselines easier to set up and use, and ideas for quantum-assisted intensity interferometry that might be employed with SCSI in the future.

Intensity Interferometry (II) is a method that can achieve high angular resolution and was first employed in the 1960s by Robert Brown and Richard Q. Twiss (HBT). Since then, significant advancements have been made, particularly in the construction of telescopes with large light collection areas, such as Imaging Atmospheric Cherenkov Telescopes (IACTs), exemplified by instruments like H.E.S.S. , MAGIC and VERITAS. Our II setup was designed to be mounted on the lid of the Phase I H.E.S.S. telescopes in Namibia. In April 2022, our first observation campaign was conducted, during which two telescopes operated in a single wavelength band. In April-May 2023, a third telescope was added, and observations were performed in two colors simultaneously for the first time in II. In this contribution I will introduce our setup and compare the different configurations, as well as present the latest results of four southern hemisphere stars.

In this talk, I will give an introduction to intensity correlations for astrophysical imaging, as pioneered by Hanbury Brown and Twiss. This triggered a wider effort for the field of quantum optics, which I will put into a larger context beyond astrophysical imaging. I will also give an overview of the past results on intensity correlations for astrophysical imaging by our group in Nice and present the ongoing effort towards resolving a white dwarf and to search for signatures of random lasing in space.

In our previous study (TI-Mucciconi-Sasamoto, Forum of Mathematics, Pi 11(e27) 1-101,2023) we introduced a deterministic time evolution of a pair of skew semistandard Young tableaux called the skew RSK dynamics.

In this talk we introduce a variant based on the column bumping in the RSK correspondence, which we call the column skew RSK dynamics. Utilizing (bi) crystal structure in the pair of skew tableaux, we show that the column skew RSK dynamics can be mapped to the single species box and ball system (BBS).  Using the mapping we obtain a relation between restricted Cauchy sums about the modified Hall-Littlewood polynomials and the skew Schur polynomials. This talk is based on the joint work with Matteo Mucciconi, Tomohiro Sasamoto and Travis Scrimshaw.

In [1] we introduced the skew RSK dynamics, which is a time evolution for a pair of skew Young tableaux (P,Q). This gives a connection between the q-Whittaker measure and the periodic Schur measure, which immediately implies a Fredholm determinant formula for various KPZ models[2]. The dynamics exhibits interesting solitonic behaviors similar to box ball systems (BBS) and is related to the theory of crystal. 

In this talk we explain basics of the skew RSK dynamics. The talk is based on a collaboration with T. Imamura, M. Mucciconi. 

[1] T. Imamura, M. Mucciconi, T. Sasamoto, 
Skew RSK dynamics: Greene invariants, affine crystals and applications to $q$-Whittaker polynomials, Forum of Mathematics, Pi (2023), e27 1–10. 

[2] T. Imamura, M. Mucciconi, T. Sasamoto, 
Solvable models in the KPZ, arXiv: 2204.08420

In this series of lectures, I will give an introduction to the theory of moments of L-functions. I will focus on important examples, such as the moments of the Riemann zeta function and Dirichlet L-functions, as well as some GL_2 families. I will also present some of the important tools for understanding moments, as well as applications of moments.