Opening Remarks Room: PI/4-405 - Bob Room

Review of HBT

• Robin Kaiser (Université Cote D'Azur)

Room: PI/4-405 - Bob Room

Intensity Interferometry with the H.E.S.S. telescopes

• Naomi Vogel (ECAP, FAU Erlangen-Nürnberg)

Room: PI/4-405 - Bob Room 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.

Workshop Talk

• David Kieda (The University of Utah)

Room: PI/4-405 - Bob Room

Progress Toward Multi-Channel Intensity Interferometry with the Southern Connecticut Stellar Interferometer

• Elliott Horch (Southern Connecticut State University)

Room: PI/4-405 - Bob Room 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.

The Multi Aperture Spectroscopic Telescope: Status and potential as an intensity interferometry facility

• Sagi Ben Ami (Weizmann Institute of Science)

Room: PI/4-405 - Bob Room The Multi-Aperture Spectroscopic Telescope is an array of 20x60cm prime-focus telescopes with single F/3 parabolic mirrors. The telescope array is being commissioned in the Negev Desert, with 10 telescopes expected to see first light by the end of the year. In the following talk, I will present the array, its various properties, including unique fiber coupling and imaging units, and its potential as an intensity interferometry facility.

Intensity Interferometer Results on Sirius with 0.25 m Telescopes

• Tom Mozdzen (Arizona State University)

Room: PI/4-405 - Bob Room We present the design and initial results of a stellar intensity interferometer using small 0.25 m Newtonian-style telescopes in an urban backyard setting. The primary purpose of the interferometer is to measure the angular diameters of stars. Recent advances in low jitter time-tagging equipment and Single Photon Avalanche Detectors have made the detection of second-order correlation signals, necessary for Intensity Interferometry as demonstrated by Hanbury Brown and Twiss in 1956, feasible with small telescopes. Using Sirius as a target star, we observe a strong second-order correlation spike with an integrated signal to noise ratio (SNR) ∼7 after 13.55 h of integration over a three-night period using a 3.3 m baseline. The measured signal agrees with the theoretical estimates of both coherence time, 𝜏coh = 0.74 ± 0.26 ps and SNR. We discuss the future expansion of this technique with multiple wavelengths simultaneously via a prism grating and multiple detectors.

Colloquium - Norm Murray Room: PI/1-100 - Theatre

Short Talks and Panel Discussion #1

• Aaron Mueninghoff (Stony Brook University)
• Peng Kian Tan (Centre for Quantum Technologies, National University of Singapore)
• Federico Izraelevitch (University of San Martin and National Research Council of Argentina)

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Review of Photon Counters

• Joshua Bienfang (National Institute of Standards and Technology)
• Karl Berggren (Massachusetts Institute of Technology)

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Workshop Talk

• Verena Leopold (Quantum Optics and Quantum Information, FAU Erlangen)

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Superconducting Nanowire Single Photon Detectors for Intensity Interferometry

• Ioana Craiciu (Jet Propulsion Lab)

Room: PI/4-405 - Bob Room Superconducting nanowire single photon detectors (SNSPDs) are of interest for intensity interferometry measurements because they have picosecond timing resolution. In addition, they work from the UV to mid-IR, with excellent eOiciency at visible and near-IR wavelengths, and are being fabricated into ever-larger detector arrays. On behalf of my colleagues in the JPL SNSPD group, I will present on the Deep Space Optical Communication (DSOC) demonstration, in which an SNSPD array was coupled to the 5 mHale telescope at Palomar, and received data at 267 Mbps from the Psyche spacecraft, the first optical communication between Earth and interplanetary space. The DSOC infrastructure at Palomar is suitable for intensity interferometry, as demonstrated by g(2) correlation (photon bunching) measurements of the stars Rigel and Procyon. I will also describe our current work on SNSPD array readout schemes, extending detector sensitivity into the mid-IR, and improving the system timing jitter of SNSPD arrays.

Workshop Talk

• Boris Korzh (Caltech)

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Review of Astro

• Charles Gammie (University of Illinois)

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Workshop Talk Room: PI/4-405 - Bob Room

Short Talks and Panel Discussion #2

• Christopher Ingenhütt (ECAP, FAU Erlangen-Nürnberg)
• Sebastian Karl (QOQI, FAU Erlangen-Nürnberg)
• Roland Walter (University of Geneva)

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Leveraging Intensity Interferometry Towards Understanding Massive Stars and Supernovae

• Jared Goldberg (Flatiron Institute)

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Workshop Talk

• I-Kai (Calvin) Chen (New York University)

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Workshop Talk Room: PI/4-405 - Bob Room

Workshop Talk

• Paul Stankus (Brookhaven National Laboratory)

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Workshop Talk

• Marios Galanis (Perimeter Institute)

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Workshop Talk

• Michael Rubel

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Bayesian Imaging for Intensity Interferometry with Deep Generative Priors

• Biwei Dai (University of California, Berkeley)

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Workshop Talk - Albert Stebbins

• Albert Stebbins (Fermi National Accelerator Laboratory)

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Workshop Talk - Prasenjit Saha

• Prasenjit Saha (University of Zurich)

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Short Talks and Panel Discussion #3

• Lifan Wang (Texas A&M University)
• Chad Bender (University of Arizona)

Room: PI/4-405 - Bob Room

Closing Remarks

• Phil Mauskopf (Arizona State Universtiy)

Room: PI/4-405 - Bob Room