Theory Seminar (High Energy/Cosmology) |
Events During the Week of May 11th through May 18th, 2025
Monday, May 12th, 2025
- Axion couplings as UV probes
- Time: 1:00 pm - 2:30 pm
- Place: Chamberlin 5280
- Speaker: Michael Nee, Harvard University
- Abstract: The couplings of axions to gauge bosons are highly restricted in Grand Unified Theories and heterotic string models. The topological nature of these couplings allows them to be matched from the UV to the IR, and the ratio of the anomaly with photons and gluons for any axion is fixed by UV physics. This implies that in these theories there is a single axion, the QCD axion, with an anomalous coupling to photons. Other light axion-like particles can couple to photons by mixing through the QCD axion portal and lie to the right of the QCD line in the mass-coupling plane. A discovery of an axion to the left of the QCD line can rule out unified theories and some heterotic models. Axion experiments are therefore probes of unification and string theory. Event recording:
- Host: Jakob Moritz
Tuesday, May 13th, 2025
- No events scheduled
Wednesday, May 14th, 2025
- No events scheduled
Thursday, May 15th, 2025
- No events scheduled
Friday, May 16th, 2025
- Quantum Entanglement Theory and Its Generic Searches at the Colliders
- Time: 1:30 pm - 3:00 pm
- Place: Sterling B343
- Speaker: Tianjun Li, Beijing, Inst. Theor. Phys.
- Abstract: We propose a new formalism for quantum entanglement, and study its generic searches at the colliders. For a general quantum system with N particles, we show that the quantum space (the total spin polarization parameter space) is complex projective space, and the classical space (the spin polarization parameter space for classical theory) is the cartesian product of the complex projective spaces. Thus, the quantum entanglement space is the difference of these two spaces. For the ff, AA, Af, fff, and ffA systems, we calculate their discrimants \Delta_i. The corresponding classical spaces are the discrimant locus \Delta=0 for ff system, and intersections of the discriminant loci \Delta_i=0 for AA, Af, fff, and ffA systems in the quantum space. We show that our criterion \Delta\not=0 is equivalent to the original Peres-Horodecki criterion for ff system. At the colliders, we can reconstruct the discriminants from various measurements, and probe the quantum entanglement spaces at exact level. This provides a fundamental approach to test the quantum entanglement. In addition, for the specific approach, we propose a generic method to calculate the quantum range and classical range for the expectation value of any physics observable, and can probe the quantum entanglement spaces which the previous way cannot test for some cases. Furthermore, we define the quantum non-locality tests as the tests for quantum entanglement space via the space-like separated measurements, which can be done at colliders as well. Event recording:
- Host: Vernon Barger