Blackboard covered with equations in the Physics & Astronomy Student Lounge

Weekly Colloquium

Most weeks during the semester, we host a scholar for a one-day visit. The visit culminates with a public talk on a topic of contemporary physics or astronomy. Students are welcome to these talks, and seniors are required to attend at least nine over the course of a year. Near the end of each semester, honors thesis students give public lectures on their work.   

Our Astronomy program is part of the Five College Astronomy Department, which hosts its own colloquium series Thursdays at 3:45 pm at UMass. 

  • Contact colloquium organizer Rachael Dunphy with any questions about colloquia, or being added to our mailing list.

September 2019

Tue, Sep 10, 2019

Welcome Back Pizza Party

Students interested in learning more about and/or declaring a Physics & Astronomy Major are invited to attend this information session. During this session you will learn about the requirements for the major as well as opportunities available for students in the Physics & Astronomy department. First year and transfer students are encouraged to attend! Meet department faculty, staff and majors!

Tue, Sep 17, 2019

Benjamin Weiss '95, MIT: "History of the solar nebula from meteorite and cometary paleomagnetism"

Theoretical studies have long suggested that magnetic fields played a central role in the formation of planetary systems by mediating angular momentum and mass transport during the protoplanetary disk stage. In particular, magnetic fields are thought to have driven stellar accretion, influenced the accretion of planetesimals, and may be associated with processes that formed the first solar system solids. However, until recently the existence and intensity of the nebular field have been unknown. Here we present analyses of the remanent magnetization in several meteorite groups demonstrating that an approximately Earth-strength nebular magnetic field existed in the inner solar system (<3 AU) during the first 3 million years after solar system formation. The strong intensity of the field supports the hypothesis that magnetic fields played a fundamental role in planet formation. Furthermore, measurements from the Philae lander on the surface comet 67P Churyumov-Gerasimenko suggest that the outer solar system (i.e., 14-45 AU) field was near-zero at the same time. Our measurements of the remanent magnetization in younger meteorites indicate that the inner solar system field then declined to near-zero by ~4 million years after solar system formation, implying that the solar nebula had dispersed by this time. This supports the hypothesis that giant planets form by a two-stage process involving formation of a rock-ice core followed by runaway gas accretion.

Tue, Sep 24, 2019

Thomas Langin, Yale: “Ultracold Molecules: A New Tool for Studying Strongly Interacting Quantum Systems”

Thomas Langin from Yale University will be speaking on Bose-Einstein Condensates (BECs).

BECs, in which the material is cold and dense enough that the wavefunctions of the particles overlap (e.g., when the DeBroglie wavelength (λ∝1/√T) equals the interparticle spacing (a∝n^(- 1/3))), are typically created by cooling N≥1000 atoms to T≤100 nK. These systems have many interesting properties, such as superfluidity, easily tunable interactions and phase coherence. However, in most atoms, interactions are limited to short-range van der Waals interactions.

At Yale, we are attempting to create BECs of SrF, a polar molecule which has strong, tunable, long-range dipole-dipole interactions. Molecules also have many easily accessible long-lived rotational states, which make them attractive for quantum information studies. In this talk, I will discuss the techniques we have implemented thus far to cool thousands of SrF molecules to T∼10μK. I will conclude by discussing our progress toward reaching lower temperatures and achieving a BEC of SrF.