Events at Physics |
Events During the Week of February 11th through February 18th, 2024
Sunday, February 11th, 2024
- Wonders of Physics
- The Wonders of Physics 41st annual show
- Time: 1:00 pm - 2:15 pm
- Place: 2103 Chamberlin
- Abstract: A fun, fast-paced physics demonstration show for all ages!
- Host: Haddie McLean
- Wonders of Physics
- The Wonders of Physics 41st annual show
- Time: 4:00 pm - 5:15 pm
- Place: 2103 Chamberlin
- Abstract: A fun, fast-paced physics demonstration show for all ages!
- Host: Haddie McLean
Monday, February 12th, 2024
- Atomic Physics Seminar
- Quantum metrology with an optical lattice atom interferometer interrogated for one minute
- Time: 12:00 pm - 1:00 pm
- Place: 5310 Chamberlin Hall
- Speaker: Cristian Panda, UC Berkeley
- Abstract: Exceptional levels of quantum control and coherence are instrumental in quantum metrology and sensing. Atom interferometers are powerful in both probing fundamental physics and everyday sensing but have been limited to measurement times of a few seconds by using atoms in free fall. I will describe how we realize interferometers with atoms suspended for an unprecedented 70 seconds in an optical lattice. This method is particularly well suited for probing localized potentials. I will show how, for the first time, we (1) optimize the gravitational sensitivity of the lattice interferometer and (2) use a system of signal inversions and switches to suppress and quantify systematic effects. This enables us to measure the attraction of a miniature source mass with record accuracy of 6.2 nm/s2, less than a billionth of Earth’s gravity and four times as good as the best similar measurements with freely falling atoms. This performance demonstrates the advantages of lattice interferometry in fundamental physics measurements. I will then show how the lattice atom interferometer can overcome the limits of current atomic gravimeters for applications in the field. Finally, I will discuss prospects for next-generation lattice atom interferometers and applications in precision measurement and quantum inertial sensing.
- Host: Thad Walker
- Plasma Physics (Physics/ECE/NE 922) Seminar
- "Stellarator optimization through coil shaping"
- Time: 12:00 pm - 1:15 pm
- Place: 1227 Engineering Hall
- Speaker: Hiroyuki Yamaguchi, National Institute for Fusion Studies
- Abstract: Stellarators/heliotrons are plasma devices that can confine plasma in a toroidal shape primarily by a magnetic field produced by external magnets. In the field of magnetic confinement fusion research, one of the challenges is the optimization of stellarators/heliotrons. In this seminar, stellarator/heliotron optimization techniques developed at National Institute for Fusion Science (NIFS, Japan) and their recent application will be explained. Optimization applying a free-form curve and the genetic algorithm will be highlighted as a very unique aspect of this technique. Interestingly, it has been found that the numerically-optimized magnetic configurations that are usually generated by crowded modular coils can be reproduced well even by a small number of helical coils.
- Host: Prof. Adelle Wright
- Theory Seminar (High Energy/Cosmology)
- Mapping New Physics from the UV to the IR
- Time: 4:00 pm - 5:00 pm
- Place: 5280 Chamberlin Hall
- Speaker: Grant Remmen, NYU
- Abstract: Using a combination of techniques spanning the modern amplitudes program, string theory, effective field theory, cosmology, and particle physics, I will show how the space of possibilities for new physics can be constrained—from both top-down and bottom-up perspectives—in a variety of contexts, ranging from quantum gravity, to predictions for colliders, to cosmic inflation.
In the first part of the talk, we will ask a bedrock question of quantum gravity: Is string theory unique? String amplitudes famously accomplish several extraordinary and interrelated mathematical feats, including an infinite spin tower, tame UV behavior, and dual resonance. I will demonstrate that it is possible to construct infinite new classes of tree-level, dual resonant amplitudes with customizable, nonlinear mass spectra. The construction generalizes naturally to n-point scattering and allows for a worldsheet integral representation. However, these constructions can be strongly constrained using multiparticle factorization, which provides a powerful new set of tools for building consistent amplitudes. In the case of a Regge spectrum, I will investigate whether string amplitudes can be bootstrapped from first principles, finding extra freedom in the dynamics that allows for a new class of dual resonant hypergeometric amplitudes.
In the second part of the talk, I will take a particle physics-driven approach, constraining effective field theories using unitarity and causality. We will construct analytic dispersion relations for the effective field theory of the standard model, bounding the size and sign of higher-dimension operators, with significant implications for CP and flavor violation. These positivity bounds allow us to connect qualitatively different experiments, including predictions for the LHC and precision measurements. I will then apply these tools in a cosmological context, building positivity bounds for the theory of multifield inflation and extracting predictions for non-Gaussianities in the cosmic microwave background.
Taken together, these two complementary initiatives comprise a program unifying phenomenological, formal, and cosmological approaches to high energy physics, bringing together powerful tools bridging fields to map the possibilities of future physics. - Host: Lisa Everett
Tuesday, February 13th, 2024
- Network in Neutrinos, Nuclear Astrophysics, and Symmetries (N3AS) Seminar
- Light Dark Sector: Inelastic Exploration
- Time: 2:00 pm
- Place: Join Zoom Meeting Meeting ID: 912 3071 4547
- Speaker: Prof. Bhaskar Dutta , Texas A&M University
- Abstract: In this talk, I will first discuss the low mass mediator models with specific examples. These models contain new particles, e.g., light mediators and light dark matter candidates. I will discuss investigations of light dark matter in these models utilizing inelastic nuclear scattering. As examples, I will use large neutrino detectors and proton-beam dump-based neutrino experiments.
- Host: Baha Balantekin
Wednesday, February 14th, 2024
- Atomic Physics Seminar
- Photonic Links for Rydberg Atom Arrays
- Time: 12:00 pm - 1:00 pm
- Place: 5310 Chamberlin Hall
- Speaker: Ivana Dimitrova, Harvard University
- Abstract: Scaling up the number of qubits available in experimental systems is one of the most significant challenges in quantum computation. A promising path forward is to modularize the quantum processors and then connect many processors using quantum channels, realized using photons and optical fibers. For Rydberg atom arrays, one of the leading platforms for quantum information processing, this could be done by developing an interface for photons, such as an optical cavity. In addition, an optical cavity can be used for fast mid-circuit readout for error detection. In this talk, I will discuss recent progress with two types of cavities and their feasibility as a photonic link. First, we show coherent control of Rydberg qubits and two-atom entanglement as close as 130um away from a nanophotonic cavity. Second, we show fast high-fidelity qubit state readout at a fiber Fabry Perot cavity. In addition, a fiber cavity also allows for cavity-mediated atom-atom gates, which could enable novel quantum networking capabilities.
- Host: Thad Walker
Thursday, February 15th, 2024
- Academic Calendar
- Spring recess
- Abstract: *Note: actual end time may vary.*
- Plasma Seminar
- Stellarators Linking Axisymmetric Mirrors (SLAM)
- Time: 1:00 pm - 2:00 pm
- Place: B343 Sterling Hall
- Speaker: Tony Qian, Princeton Universtiy
- Abstract: This talk motivates the study of using optimized stellarators to link large volume axisymmetric mirrors for the purpose of fusion energy. There are significant challenges in scaling optimized stellarators to fusion reactors, in particular the construction of a large volume 3D device which has a breeding blanket integrated with complex geometry. Meanwhile, mirrors have large volume and simple coils, but face plasma physics issues due to open field line end loss, velocity space anisotropy, MHD stability, and turbulence (once confinement allows sufficiently high temperature gradients). We propose a hybrid approach that overcomes challenges of each, enabled by modern stellarator optimization. It consists of axisymmetric mirror cells linked by stellarator segments. Most of the plasma volume is in the mirror cells, where the typical loss cone is replaced by a source cone from the stellarator. The goal is to combine the simple engineering of axisymmetric, linear mirror cells with the good plasma confinement and stability of stellarators. Two questions arise: do such flux surfaces exist? If so, are they MHD stable? We discuss a basic plasma physics experiment that can be built to address these questions using the unique capabilities at UW-Madison.
- Host: Jan Egedal
- Theory Seminar (High Energy/Cosmology)
- Tabletop to Telescope: Unraveling the Mystery of Dark Matter
- Time: 4:00 pm - 5:00 pm
- Place: 5280 Chamberlin Hall
- Speaker: Tanner Trickle, Fermilab
- Abstract: Recent years have seen a dramatic expansion in ideas to search for dark matter beyond the WIMP paradigm. In this talk we'll discuss a diverse range of new approaches, starting with small-scale tabletop experiments. These experiments target dark matter particles far lighter than WIMPs using innovative ideas from condensed matter physics and quantum sensing. New calculations have transformed our understanding of how dark matter can interact with electrons and are essential for current experimental efforts. Additionally, we'll explore how collective excitations, e.g., phonons and magnons, can revolutionize the way we search for dark matter. Complementing these tabletop experiments, pulsar timing arrays are exceptionally sensitive to new physics on galactic scales. While their primary purpose is to detect stochastic gravitational wave backgrounds, we'll show how their extraordinary precision can be leveraged to hunt for both the lightest, and heaviest, dark matter candidates.
- Host: Lisa Everett
Friday, February 16th, 2024
- No events scheduled
Saturday, February 17th, 2024
- Wonders of Physics
- The Wonders of Physics 41st annual show
- Time: 1:00 pm - 2:15 pm
- Place: 2103 Chamberlin
- Abstract: A fun, fast-paced physics demonstration show for all ages!
- Host: Haddie McLean
- Wonders of Physics
- The Wonders of Physics 41st annual show
- Time: 4:00 pm - 5:15 pm
- Place: 2103 Chamberlin
- Abstract: A fun, fast-paced physics demonstration show for all ages!
- Host: Haddie McLean
Sunday, February 18th, 2024
- Wonders of Physics
- The Wonders of Physics 41st annual show
- Time: 1:00 pm - 2:15 pm
- Place: 2103 Chamberlin
- Abstract: A fun, fast-paced physics demonstration show for all ages!
- Host: Haddie McLean
- Wonders of Physics
- The Wonders of Physics 41st annual show
- Time: 4:00 pm - 5:15 pm
- Place: 2103 Chamberlin
- Abstract: A fun, fast-paced physics demonstration show for all ages!
- Host: Haddie McLean