Events

Soft factorization has been shown to hold to sub-leading order in QED and to sub-sub-leading order in perturbative quantum gravity, with various loop and non-universal corrections that can be found. In a recent paper, we show that all terms factorizing at tree level can be uniquely identified as boundary terms that exist already in the classical expressions for the electric current and stress tensor of a point particle.

The most precise of the direct measurements of the current rate of cosmic expansion (the Hubble constant) is inconsistent with the even more precise, but indirect, model-dependent inferences. In particular the Riess et al. (2020) measurement is more than four standard deviations higher than the inference based on the standard cosmological model, with its free parameters constrained by Planck satellite observations of the cosmic microwave background.

Abstract: (please see this link)

An electron that multiphoton ionizes is immediately subject to the light's electric field that will control its short-term future.  This control enables a gas of atoms to produce intense VUV or soft X-ray beams.  Since we can precisely control the infrared beam, we can synthesize attosecond soft X-ray pulses - pulses that are the shortest controlled events ever systematically produced.  For a complex atom (such as xenon), the recollision electron shares its energy in any multi-electron interaction.

CM Seminar - Thu, March 25, 10am (PST)
https://ubc.zoom.us/j/64183011430?pwd=U2lFNXEwSmlBRWVBdTR5OG1ZdlVSZz09
Meeting ID: 641 8301 1430

Abstract:

Magnetic fields thread our Milky Way Galaxy, influencing interstellar physics from cosmic ray propagation to star formation. The magnetic interstellar medium is also a formidable foreground for experimental cosmology, particularly for the quest to find signatures of inflation in the polarized cosmic microwave background (CMB). Despite its importance across scientific realms, the structure of the Galactic magnetic field is not well understood.

Black holes are interesting spacetime configurations predicted by general relativity. When quantum mechanics is taken into account, black holes are found to emit thermal radiation, called "Hawking radiation".
During the past couple of years a surprising new way to compute its entropy has emerged. This result indicates that the black hole formation and evaporation is consistent with standard quantum mechanical laws.

Abstract:

The success of gravitational wave observations of stellar mass black hole mergers and neutron star mergers has proven that observational gravitational wave astronomy has an important part to play in coming years. However, ground-based laser interferometers can access only a limited portion of the gravitational wave spectrum.

Abstract: New Jersey Institute of Technology's Expanded Owens Valley Solar Array (EOVSA) has amply demonstrated the power of radio imaging spectroscopy for imaging and quantitative diagnostics of both the flaring and non-flaring Sun.  The unique sensitivity of radio emission to the flaring coronal magnetic field has been dramatically shown in a series of recent papers, along with accelerated-electron diagnostics in the same volume.  The coming solar maximum (cycle 25) is slated to peak in 2025-2026, which promises to bring new space- and ground-based instruments together with

Abstract: (see this link)

The connection between physics and finance goes back hundreds of years, and the names of the earliest physicists who studied finance may be surprising.  In the 18^th century Bernoulli discovered Euler's constant e when investigating compound interest; mo

No experiment today provides evidence that gravity requires a quantum description. It has been suggested that one can at least exclude the possibility for semiclassical gravity by performing an experiment whose outcome cannot be explained by a purely classical source mass configuration.

Lyman-alpha emission is produced ubiquitously by excited hydrogen, so it is a powerful tracer of the interactions among gas, stars, and AGN that shape galaxy formation. However, the resonant scattering of this emission line makes its interpretation complex. In this talk, I will describe three related surveys of galaxies at z~2-3 that make use of Lyman-alpha emission: the Keck Baryonic Structure Survey (KBSS), the KBSS-Lya, and the Keck Lyman Continuum Survey (KCLS).

Abstract: (see this link)

While motorsports events can appear to the general viewing public as a parade of cars driving around tracks in circles, in reality race drivers operating their cars at the grip limit are constantly on a razor's edge, balancing and adjusting the behavior of the car with a variety of inputs and techniques that are foreign to the average road driver.

https://ubc.zoom.us/j/64183011430?pwd=U2lFNXEwSmlBRWVBdTR5OG1ZdlVSZz09
Meeting ID: 641 8301 1430
Passcode: 113399

https://ubc.zoom.us/j/68506225698?pwd=S2ZBRGsrbzZBQVVZZFNwYk5ZSEduQT09
Meeting ID: 685 0622 5698
Passcode: 113399

It has been suggested that Planck-scale "spacetime foam" could have significant macroscopic consequences, perhaps even offering a way to address the cosmological constant problem.  I will describe progress in constructing a locally spherically symmetric minisuperspace model with a positive cosmological constant that may shed light on th

 Are you a first year UBC student interested in physics or astronomy degree programs? Or, you are just curious in general, wondering what students in PHAS programs study? Join us on Monday, March 1st at 5:30pm for "Meet Your Major" - chat with PHAS academic advisors and student representatives to learn more about options available for you!

Register now at the Meet Your Major website.

Is your data too complex? This can help. In this talk, we will introduce the scattering transform, a novel approach to extract information from complex data. We will explain its principle and show that it shares mathematical similarities with convolutional neural nets — but it does not require any training and is interpretable! We will demonstrate its power by applying it to datasets in astronomy, cosmology and oceanography for parameter estimation and outlier detection.