We are very pleased to welcome Dr. Latham Boyle to York as this year’s keynote speaker. Please join us for his talk during the conference on Wed May 15 at 11:00am in LSB 105. Lunch will follow for all attendees at 12:00 in LSB 106.

Dr. Boyle is a faculty member at the Perimeter Institute for Theoretical Physics and will be sharing some fascinating ideas coming out of his current research.

CPT-Symmetric Universe

Abstract: I will introduce our recent proposal that the state of the universe does *not* spontaneously violate CPT. Instead, the universe after the big bang is the CPT image of the universe before it, both classically and quantum mechanically. The pre- and post-bang epochs comprise a universe/anti-universe pair, emerging from nothing directly into a hot, radiation-dominated era. CPT symmetry selects the QFT vacuum state on such a spacetime, providing a new interpretation of the cosmological baryon asymmetry, as well as an economical explanation for the cosmological dark matter. Requiring only the standard three-generation model of particle physics (with right-handed neutrinos), a Z_2 symmetry suffices to render one of the right-handed neutrinos stable. One can calculate its abundance from first principles: matching the observed dark matter density requires its mass to be 4.8 x 10^{8} GeV. Several other testable predictions follow: (i) the three light neutrinos are Majorana and allow neutrinoless double beta decay; (ii) the lightest neutrino is massless; and (iii) there are no primordial long-wavelength gravitational waves. The proposal also has interesting things to say about the strong CP problem and the observed electrodynamic arrow of time.

(Based on arXiv:1803.08928 and arXiv:1803.08930 with Kieran Finn and Neil Turok, and forthcoming work.)

This year’s PAGE Conference schedule is now available:

The annual PAGE conference is an opportunity for students in the department to:

• share their research with the York Physics community
• practice presenting in a familiar, low-stakes environment
• hear about the research being done by their peers
• hear an awesome talk from a keynote speaker (to be announced)

All are welcome to attend and lunch is provided for all. You can find out more about the conference here. Also, prizes are awarded to the best speakers.

The next Conference is schedule for Wednesday, May 15, 2019.

See the schedule from last year’s conference HERE.

If you are interested in participating, please send an email to page@yorku.ca.

Hope to see you there!

Probing Cochlear Tuning in the Marmoset

The biomechanical challenges our ears face are immense, as they must detect very fast (0.01-200 kHz), very small (sub-angstrom) motions in warm, salty water. Nonetheless, their performance is remarkable: A dynamic range spanning over 12 orders of magnitude of energy, the lower end of which providing sensitivity below the thermal noise floor. Furthermore, the ear exhibits a striking manifestation: It not only detects sound but also generates and subsequently emits it as well. These very faint sounds, known as otoacoustic emissions (OAEs), can be detected in the ear canal using a sensitive microphone. Thought to be a by-product of an underlying amplification mechanism, they provide a valuable probe into the biophysics of the cochlea, where study is otherwise extremely difficult (given that the inner ear is completely encased in the hardest bone in the body). It has been demonstrated that a certain type of evoked emission (stimulus-frequency otoacoustic emissions, SFOAEs) can be used to objectively estimate the frequency selectivity of the cochlea. Comparative data suggests humans may be unique in this regard, with relatively sharp tuning. The goal of this study was to help establish how tuning may be correlated with basilar-membrane (BM) length. Because inter-species comparisons can be complicated by phylogenetic differences, we sought to minimize these confounds by measuring SFOAE delays in the marmoset (Callithrix jacchus), a New World primate with a relatively short BM (~14 mm) and good high frequency hearing. These data suggest a correlation between SFOAE delay and BM length among primates, although the comparison with cat demonstrates that BM length cannot, by itself, explain delay differences across species. If SFOAE delays provide a reliable measure of cochlear tuning as proposed, the data suggest that tuning is sharper in marmoset than in cats below 8 kHz, encompassing a frequency range relevant for the monkey’s vocalizations.