URI Physics Colloquium
The URI Physics department hosts an ongoing speaker series each academic year, which features physics experts from URI and other universities, as well as scientific organizations.
During the fall and spring semesters, colloquia are held in East Hall, Room 112. Refreshments are served about half hour before each talk.
All are welcome, and there is no fee to attend.
Schedule for Spring 2025 :
| Date | Speaker | Title | Location | Time |
|---|---|---|---|---|
| Friday, January 31, 2025 | Jennifer Borsavage | Low-Z Targets for MV Beam Production in Radiation Therapy | East Hall 112 | 4:00 pm |
| Friday, February 7, 2025 | Mark Semco | The path towards Laser-Cooling and Trapping a Neutral Molecule for Quantum Science | East Hall 112 | 4:00 pm |
| Thursday, February 13, 2025 | Ning Bao | Quantum Information and Quantum Gravity | East Hall 112 | 4:00 pm |
| Friday, February 21, 2025 | N/A | N/A | N/A | 4:00 pm |
| Friday, February 28, 2025 | Student Presentations | TBA | East Hall 112 | 4:00 pm |
| Monday, March 3, 2025( 4:30 PM) | Sean Carroll | Extracting the Universe from the Wave Function | Bliss Hall 190 | 4:30pm |
| Friday, March 14, 2025 | N/A(Spring Break) | N/A | N/A | |
| Friday, March 21, 2025 | N/A | N/A | N/A | |
| Friday, April 4, 2025 | Alessandra Corsi | Multi-messenger observations of gravitational waves sources: from LIGO to Cosmic Explorer. | East Hall 112 | 4:00 pm |
| Friday, April 11, 2025 | Ilya Safro | TBA | East Hall 112 | 4:00 pm |
| Friday, April 11, 2025 | Vincenzo Tamma | Ultimate quantum sensing sensitivity through multiphoton interference with scalable resources | East Hall 112 | 4:00 pm |
| Friday, April 11, 2025 | Suhail Zubairy | Interaction-free measurement and beyond | East Hall 112 | 4:00 pm |
| Friday, April 18, 2025 | Spencer Rogers | Nonclassicality of Mixed States with Photon Number Coherence | East Hall 112 | 4:00 pm |
| Friday, April 25, 2025 | George Gibson | Just What is the Connection Between Physics and Music? | East Hall 112 | 4:00 pm |
Abstracts:
Low-Z Targets for MV Beam Production in Radiation Therapy
Image guidance is employed in radiation therapy to ensure accurate patient setup prior to treatment delivery. Modern linear accelerators are equipped with two imaging systems for use in image guidance: 1) a megavoltage system which shares the same beamline as the treatment beam and 2) a kilovoltage system oriented orthogonally to the treatment beam. Due to the spectral differences, the kV system offers improved image quality per unit dose compared to the MV beam, owing to increased photoelectric interactions. While the kV system offers improved image quality, this system presents a geometrical disadvantage, preventing visualization of the target volume from the treatment beam’s eye view. The achievable MV image quality can be improved by implementing a low atomic number target for photon beam production. Due to the cubic dependence of the photoelectric cross section on Z, low-Z targets yield a higher proportion of low-Z photons compared to a conventional high-Z target. In this talk, I present the theory of MV beam production using a low-Z target and my experience implementing a 2.5 MV sintered diamond target beam on a modern linear accelerator.
The path towards Laser-Cooling and Trapping a Neutral Molecule for Quantum Science
I aim to provide a digestible walkthrough of the key techniques and challenges faced when working towards building a cold, dense trap of neutral molecules. Laser-cooled molecules promise access to a diverse range of research directions including quantum simulation, ultracold organic chemistry and improved precision measurements. At present only a small list of molecules have been successfully laser cooled and magneto-optically trapped. My PhD research goal is to bring AlCl to that list. Molecules, such as AlCl, appear particularly versatile by combining favorable properties for optical cycling and a sizable electric dipole moment (~1 D) with an electronic structure analogous to that of alkaline earth atoms. This structure provides both strong optical transitions for efficient laser-cooling and trapping and narrow optical transitions with the potential for manipulating quantum states and detecting interactions. This versatility comes at the expense of technical complexity as (similar to alkaline earth atoms) the strong optical cycling transition in AlCl demands energetic photons at 261 nm and has a high saturation intensity. Fortunately, recent progress by our group [1] and others has realized watt-level lasers in the deep UV and made the realization of large, trapped samples of laser-cooled AlCl a possibility. By the end I will give an experimental update on our progress towards magneto-optically trapping AlCl in 3D.
Quantum Information and Quantum Gravity
I will discuss interconnections between quantum gravity and quantum information science, focusing on aspects where they inform each other. Particular topics will include entanglement entropy, black holes, thermodynamics, and quantum error correction.
Ultimate quantum sensing sensitivity through multiphoton interference with scalable resources
Quantum interference is one of the most intriguing phenomena in quantum physics at the very heart of the development of quantum technology in the current quantum industry era. It underpins fundamental tests of the quantum mechanical nature of our universe as well as applications in quantum computing, quantum sensing and quantum communication.
I will give an overview of multiphoton sensing techniques enabling the ultimate quantum sensitivity, given by the quantum Cramér-Rao bound, by employing sampling measurements which resolve the inner degrees of freedom, such as time, frequency, position, and polarization, of single photons interfering at a beam splitter. This includes: estimation of the transverse position of a given source for applications in super-resolved single-molecule localization microscopy, by circumventing the requirements in standard direct imaging of camera resolution at the diffraction limit, and of highly magnifying objectives ; multi-parameter estimation of the polarization state of two interfering photonic qubits for applications in quantum information networks ; imaging of nanostructures, including biological samples, and nanomaterial surfaces, with arbitrary values of thickness through estimation of photonic time delays; ultimate quantum sensitivity in single-photon spectroscopy based only on sampling time-resolved detections; superresolution imaging beyond the Rayleigh limit of incoherent sources via two-photon interference sampling measurements in the transverse momenta.
I will also describe quantum interference techniques based on linear optical networks with squeezed light for the measurements with Heisenberg-scaling sensitivity of a single parameter or multiple parameters. Applications can range from environmental sensing to high-precision biomedical imaging, characterization of nanomaterials, navigation, gravity tests and quantum networks of high-precision clocks. This research opens a new paradigm based on the interface between the physics of quantum interference and quantum sensing with experimentally feasible “real world” photonic sources
Interaction-free measurement and beyond
It is truly amazing that, even today, an understanding of simple systems can lead to startling new ideas and devices. In this talk I shall discuss how the simplest quantum optical devices like mirrors and beam splitters can be employed in areas such as interaction-free measurement, quantum secure communication, generation of elusive Schrodinger-cat states of the radiation field, and communication with invisible photons.
Bio: Professor M. Suhail Zubairy received his Ph.D. from the University of Rochester in 1978. He is presently a University Distinguished Professor in the Department of Physics and Astronomy and the holder of the Munnerlyn-Heep Chair in Quantum Optics at Texas A&M University. He has made several pioneering contributions in the fields of Quantum Optics and Laser Physics. He is the co-author of two books, one on Quantum Optics and the other on Quantum Computing Devices. Recently he published a book entitled Quantum Mechanics for Beginners. In recognition of his contributions to the field of Quantum Optics and Laser Physics, Prof. Zubairy has received many honors including the Willis E. Lamb Award for Laser Science and Quantum Optics, Alexander von Humboldt Research Prize for Distinguished Scientists, the Changjiang Distinguished Award, the Outstanding Physicist Award from the Organization of Islamic Countries, the Abdus Salam Prize in Physics, the International Khwarizmi Award, and the George H. W. Bush Award for Excellence in International Research.
Extracting the Universe from the Wave Function
Abstract: Quantum mechanics is a theory of evolving vectors in Hilbert space. Many features that we generally take for granted when we use quantum mechanics — classical spacetime, locality, the system/environment split, collapse/branching, preferred observables, the Born rule for probabilities — should in principle be derivable from the basic ingredients of the quantum state and the Hamiltonian. I will discuss recent progress on these problems, including consequences for emergent spacetime and quantum gravity.
Multi-messenger observations of gravitational waves sources: from LIGO to Cosmic Explorer.
The direct detection of gravitational waves is revolutionizing our view of the universe and has opened a new era in the field of time-domain multi-messenger astronomy. In this talk, I will summarize key open questions on the astrophysics of stellar-mass compact objects associated with multi-messenger transients. Then, I will describe the scientific reach and discovery potential of current and future ground-based gravitational-wave detectors, from LIGO-Virgo-KAGRA to Cosmic Explorer. I will emphasize synergies with electromagnetic facilities, particularly those operating in the radio band. I will conclude with a few highlights on prospects for extending multi-messenger studies to compact objects across the mass spectrum.
Nonclassicality of Mixed States with Photon Number Coherence.
Nonclassicality measures can be used to characterize exotic states for quantum-enhanced sensing. One such measure is the operational resource theory (ORT) measure, which is both resource-theoretic and lower-bounded by metrological power. Calculating the ORT measure for mixed states is challenging, but was previously achieved for states that are diagonal in the photon-number basis. We review these concepts and discuss recent results quantifying the nonclassicality of mixed states with photon number coherence. Among these findings is that for partially coherent mixtures of |n+1> and |n> (single-photon and vacuum, if n=0), the ORT measure is constant under changes to the photon number coherence below a certain threshold, an effect reminiscent of entanglement sudden death.
Just What is the Connection Between Physics and Music?
What we are nowadays hearing of the language of spectra is a true “music of the spheres” within the atom, chords of integral relationships, an order and Harmony that becomes ever more perfect in spite of the manifold variety.” – Sommerfeld (1919).