Majumder Group News
Congratulations to Abdullah Nasir ’20 on his graduation. It’s been a pleasure having him as part of our lab team, starting with a summer after his freshman year, and now culminating with excellent thesis work, especially in this crazy year in which much less was possible in the lab physically. We look forward to having him around for a little longer this summer, and then wish him the very best of luck at Harvard where he will be starting in the physics Ph.D. program this fall.
Here is his thesis: Nasir_Thesis
We are also participating in virtual DAMOP 2020, and have prepared this poster: DAMOP2020 Poster
And, undaunted, we had our annual Ephs @ DAMOP gathering, which was exceptionally well-attended, with Williams graduates from 1966 to 2021 represented, as well as current and former Majumder group postdocs!
We look forward to a summer of productive, if still virtual work with incoming thesis students Gabriel Patenotte ’21, and Patrick Postec ’21.
Its been quite a six months since the last update. I want to salute the amazing work of postdoc John Lacy and thesis student Abdullah Nasir ’20, as well as junior Gabriel Patenotte ’21 who will be starting his thesis work this summer. In a time of unprecedented disruption and crisis, all of the team members have remained focused, productive, and as optimistic and positive as possible.
Through the winter and early spring, we focused as a team on two projects :
(1) translating our Faraday Rotation Spectroscopy (FRS) technique to our atomic beam apparatus, and to completely rebuilding our source / furnace and vacuum system to accommodate a new Pb atomic beam source.
(2) optimizing design and testing the behavior of our new 368.5 nm UV diode laser system which operates slightly below zero (Celsius) and now allows routine single-mode tuning around the Pb (6s2 6p2) 3P1 –> (6s2 6p7s) 3P0 E1 transition, which we have observed in a vapor cell.
Next steps as of March were to optimize the beam operation, and search for M1 FRS signals in the ABU. With the arrival of COVID-19, we went into a more virtual, shutdown mode. John and Abdullah have been focusing both on a series of theory / simulation problems associated with measuring Polarizability (static E-field) in the presence of magnetic field necessary for FRS, as well as studying the small tensor polarizability component of the 3P1 state.
We look forward to a slow return to lab work soon.
Welcome to our new postdoc, Dr. John Lacy, who arrived at the beginning of November from the UK, where he recently completed his D.Phil. at U. Sussex, having earlier done his Bachelors degree at Cambridge Univ. John did his doctoral work in the area of development of novel electron Penning traps. He is quickly integrating himself into all Majumder lab projects, working closely with Abdullah Nasir ’20 (thesis student) and Gabriel Pattenote ’21 and Declan Smith ’21 (research students) on both vapor cell and atomic beam experiments.
Our latest Pb Faraday spectroscopy work, completed in collaboration with theory co-authors Marianna Safronova and Sergey Porsev, has appeared in Physical Review A:
We are working to extend this high-precision polarimetry technique to the atomic beam environment, for spectroscopy and polarizability measurement in Lead, and also for precise isotope shift / HFS work in a ‘double polarimeter’ setup using our lead furnace.
We have settled in to our new lab in the South Science Building. This year saw completion of our Lead transition amplitude / Faraday polarimetry measurement, led by postdoc Dan Maser. This work, with Safronova group co-authors, is being written up now.
Sophomores Gabriel Pattenote ’21 and Sameer Khanbhai ’21 continued their work with our group throughout the year. Gabriel and Dan designed, constructed, and successfully tested a new UV laser system (368.5 nm) with which we did preliminary excited-state spectroscopy of Pb atoms in a cell. Abdullah Nasir ’20 returned to the group to work over WSP in January, and will begin his senior thesis work in the Majumder lab this summer pursuing Pb atomic beam spectroscopy experiments. He will be joined by rising juniors Declan Smith ’21 and Duncan McCarthy ’21 this summer.
vapor cell furnace and polarimetry ABU reincarnated in new lab!
Tiku and Dan attended the 50th annual DAMOP meeting in Milwaukee, WI at the end of May. Dan presented a 10-minute talk on our Pb quadrupole transition amplitude measurement. PPT slides here:
We also presented a poster on this and upcoming work in the group:
We caught up with many recent alums!
Justin Brown ’05, Nathan Schine ’13, Ben Augenbraun ’15, Allison Carter ’16, Nathaniel Vilas ’17, Prof. Charlie Doret ’02, Tori Borish ’12
Majumder group alums @ DAMOP 2019
(L-R): Charlie Doret ’02 (Asst Prof @ Williams), Ben Augenbraun ’15, Dr. Dan Maser (Asst. Prof @ Conn College), Nathaniel Vilas ’17, Nathan Schine ’13, Allison Carter ’16
Congratulations to Postdoc Dan Maser, who has accepted a tenure-track faculty position at Connecticut College in New London, CT!! Dan will be building up a new lab to do laser spectroscopy of trace atmospheric molecules using frequency-comb technology. We will truly miss Dan’s energy, expertise, and leadership in the group, but wish him the very, very best in his new adventure!
Looking forward to unpacking and setting up our experiments in our brand new lab, Room 006 of the South Science Building, with Postdoc Dan Maser, and research assistants Gabe Pattenote ’21, and Sameer Khanbhai ’21.
Postdoc Dan Maser and thesis student Bingyi Wang ’18 attended the annual DAMOP meeting, as well as the precision measurement workshop that preceded it, in Fort Lauderdale, FL. Here is a .pdf of the poster that they presented on our recent Indium polarizability measurements, including our latest results published in February.
DAMOP poster_2018 (1.6 MB)
Congratulations to Bingyi Wang ’18, who graduated magna cum laude & Phi Beta Kappa, on June 3rd, an is headed to Stanford this fall. Here is her thesis:
Congratulations to Bingyi Wang ’18, current thesis student, for being chosen as one of the inaugural cohort of Knight-Hennessey Scholars at Stanford University, where she will be beginning in the Physics Ph.D. program. Bingyi was one of 50 scholars out of several thousand applicants!
Our latest Indium atomic beam polarizability measurements have been published, with Marianna Safronova’s group contributing ab initio calculations, so that for the first time we can systematically compare two side-by-side calculational methods (the so-called Coupled Cluster method and the Configuration Interaction / All-order method). Our latest results for the polarizability of the 7p states and earlier results for the 6p and 6s states show clear ‘preference’ for the latter theory method for the case of these excited states in this trivalent atom.
Co-authors from our group are Nathaniel Vilas ’17, Bingyi Wang ’18, and recent and current postdocs Milinda Rupasinghe and Dan Maser.
We are very happy to welcome new postdoc Dr. Daniel Maser to our group. Dan completed his undergraduate degree at Berkeley, and his Ph.D. at the Univ. of Colorado, working in Scott Diddams’ lab at NIST building new frequency-comb-based mid-IR laser sources for sensing applications.
Dan will immediately join current thesis student Bingyi Wang ’18 as we complete our latest indium ABU polarizability experiment, and also continue our Pb transition amplitude / Faraday polarimetry work begun last year by Eli Hoenig ’17.
DAMOP 2017, Sacramento, CA June 5-9, 2017
A great week in Sacramento with lots of current and former students and colleagues!
Current Majumder group attendees: Nathaniel Vilas ’17, Eli Hoenig ’17, Postdoc Milinda Rupasinghe, Joined by Prof. Charlie Doret, three of his students, and Prof. Swati Singh.
Here are the posters we presented on the Pb and In experiments:
Pb Faraday spectroscopy / E2 transition measurement
In atomic beam polarizability measurements
Congratulations to Eli Hoenig ’17 and Nathaniel Vilas ’17 who completed their senior theses describing excellent work and exciting new results in two experiments:
Nathaniel Vilas – two-step atomic beam spectroscopy / polarizability measurements of the indium 7p states: Vilas Thesis (4 MB)
Eli Hoenig – Lead vapor cell polarimetry of both the 1279 nm M1 and 939 nm E2 transitions to measure absolute transition linestrengths: Hoenig Thesis (6 MB)
We have resurrected our optical polarimeter, with plans to measure the M1 and E2 ground-state transition amplitudes in Lead (comparing Faraday Rotation signals for a common magnetic field and in the same vapor cell) to test new atomic theory calculations. Some pretty impressive measurements (thanks Eli!) of intrinsic angle noise at the 0.1 μradian / √Hz level:
Received this exciting news in a letter from the APS this week:
On behalf of the American Physical Society, it is my pleasure to inform you that you have been awarded the 2017 Prize for a Faculty Member for Research in an Undergraduate Institution:
“For contributions to the precision measurement of atomic properties, and sustained, inspirational mentorship of undergraduate researchers.”
This could not have happened without an institution committed to supporting research with undergraduates, as well as great colleagues, and, most of all, a wonderful and talented collection of Williams students with whom I’ve had the privilege of working for the past 20 years. I’m very grateful!
Group picture from summer (L-R: Nathaniel Vilas ’17, PKM, Eli Hoenig ’17, Bingyi Wang ’18)
Rising thesis students Eli Hoenig ’17, Nathaniel Vilas ’17, as well as rising junior Bing Yi Wang ’18 and postdoc Milinda Rupasinghe completed a series of vapor cell spectroscopy experiments in thallium and indium using our two-step spectroscopy technique. All the second-step transitions were in the red 650-690 nm range and so by exchanging diodes we measured hyperfine structure and isotope shifts all with sub-MHz accuracy. This work is now being written up for publication.
Meanwhile, our paper describing the latest atomic beam polarizability measurement (in the indium 6p1/2 excited state) was published in Phys. Rev. A in August with Ben Augenbraun ’15 and Allison Carter ’16 as co-authors.
Congratulations to Allison Carter ’16, and Sauman ’16 who graduated on June 5th, and completed very successful senior thesis projects in the lab this year! Good luck to Allison, who is starting in the Physics Ph.D. program at U. Maryland, and to Sauman, who is starting in the Mech. Eng. Ph.D. program at U. Colorado this fall. We will miss you!
This year’s theses:
Allison: indium 6p1/2 state polarizability measurement using the atomic beam (2.7 MB)
Sauman: thallium 8p1/2-state HFS/ IS shift work using the heated vapor cell (8.4 MB)
Oh — and something to make me feel old: Picture of my very first set of thesis students who returned this June for their 20th reunion!! (Kyle Downey ’96, Paul Boerner ’96):
DAMOP 2016, May 23-27 2016, Providence, RI
The proximity of this year’s DAMOP conference allowed Profs. Doret and Majumder to fill up a van with Ephs and drive. Accompanying them were graduating seniors Allison Carter ’16, Sauman Cheng ’16, and Ariel Silbert ’16. Also attending were Nathaniel Vilas ’17 and Sierra Jubin ’17, who will be starting thesis work this summer, and also postdoc Milinda Rupasinghe.
Ben Augenbraun ’15 attended the conference, and formally received his 2015 APS Apker Award certificate, and gave an excellent invited talk on his thesis work.
Many other Ephs (19 in all!) were in attendance (spanning more than a half century of graduating classes!):
Here are all of the current and former Majumder group thesis students in attendance:
(L-R) Allison Carter ’16 (U. Maryland), Nathaniel Vilas ’17, Sauman Cheng ’16 (U. Colorado), Ben Augenbraun ’15 (Harvard), Charlie Doret ’02 (Harvard, GTRI, Williams!), PKM, Colin Bruzewicz ’05 (Yale, Lincoln Labs), Nathan Schine ’13 (U. Chicago), Paul Hess ’08 (Harvard, U. Maryland).
And here we are at the poster session with our two group posters behind:
PDFs of posters presented:
Indium 6p1/2-state Atomic Beam / Stark shift measurement
Thallium 8p/12-state HFS/IS spectroscopy
Congratulations to thesis student Ben Augenbraun ’15 who is the 2015 A.P.S. LeRoy Apker Award WINNER !!! (the Apker Award is the nation’s top honor for undergraduate physics research). We wish Ben the very best as he begins in the Ph.D. program at Harvard this fall.
Former group member, and now Williams physics department colleague, Charlie Doret ’02 was the 2002 Apker Award winner. All together FIVE Williams physics majors have won this award.
Here is a link to Ben’s undergraduate thesis:
Augenbraun thesis (6.2 MB)
We welcome Sauman Cheng ’16 and Allison Carter ’16 to the lab this summer , who will begin their thesis work, and will be joined by Nathanial Vilas ’17, Milinda, and Prof. Majumder.
Here is a picture of the summer 2015 research group:
DAMOP 2015, Columbus, OH:
Ben Augenbraun ’15, Postdoc Milinda Rupasinghe, and Prof. Majumder attended the 2015 DAMOP conference in Columbus, OH. Here are some highlights:
Ben Augenbraun ’15, Nathan Schine ’13 and PKM in front of latest group poster on two-step, atomic beam Stark shift experiment in Indium.
[email protected] 2015: (L-R) Ben Augenbraun ’15,Dr. Justin Brown ’05 (Draper Labs), Paul Hess ’08 (Harvard, JQI), Colin Bruzewicz ’05 (Yale, Lincoln Labs),Prof. Charlie Doret ’02 (Harvard, Williams College), Dr. Milinda Rupasinghe (postdoc, Majumder group),Nathan Schine ’13 (U. Chicago),Ryan Carollo ’05 (U. Conn), Prof. Chad Orzel ’93 (Union College), PKM, Prof. Josh Grossman ’96 (St. Mary’s College)
Former Majumder group thesis students @ DAMOP: Paul Hess ’08 (Harvard), Ben Augenbraun (Harvard), Charlie Doret (Harvard), Nathan Schine (Chicago), Colin Bruzewicz (Yale)
Welcome to new postdoc, Dr. Milinda Rupasinghe, who joined us in January from Oklahoma, where he did his Ph.D. work in atomic physics.
We gratefully acknowledge the support of our new 3-year NSF grant #1404206 which supports our postdoc, summer studies, and equipment and supply needs.
DAMOP 2014, Madison, WI:
Here is the latest from our group, including recent photos, DAMOP 14 conference posters, senior honors theses, and publications
[email protected] 2014: (L-R) Prof. Chad Orzel ’93 (Union College), Prof. Josh Grossman ’96 (St. Mary’s College), Prof. Charlie Doret ’02 (Williams College), PKM, Nathan Schine ’13 (U. Chicago), Dr. Justin Brown ’05 (Draper Labs), Ryan Carollo ’05 (U. Conn), Ben Augenbraun ’15
Nathan Schine ’13 (now at U. Chicago) and Ben Augenbraun ’15 at Poster Session w/indium atomic beam poster, DAMOP 14.
POSTERS FROM DAMOP 2014, Madison, WI, June 2-5
Atomic Beam / Stark shift poster (2.8 MB)
Vapor Cell / 2-step Spectroscopy poster (3.8 MB)
RECENT SENIOR HONORS THESES AND PUBLICATIONS
INDIUM ATOMIC BEAM WORK
- Senior Honors Thesis of Allison Carter ’16 (now at U. Maryland): Carter thesis (2.7 MB)
- Senior Honors Thesis of Ben Augenbraun ’15 (now at Harvard Univ.): Augenbraun thesis (6.2 MB)
- Senior Honors Thesis of Nathan Bricault ’14 (now at Cambridge Univ): Bricault_thesis
- Senior Honors Thesis of Nathan Schine ’13 (Simon group, U. Chicago): Schine_thesis
Phys. Rev. A paper describing this work:
THALLIUM VAPOR CELL WORK
- Senior Honors Thesis of Sauman Cheng ’16 (now at U. Colorado): Cheng thesis
- Senior Honors Thesis of Gabby Vukasin ’14 (now at Stanford Univ): Vukasin_thesis
- Senior Honors Thesis of David Kealhofer ’13 (now at UCSB): Kealhofer_thesis
Phys. Rev. A paper describing this work: