Prof. John Davis (Univ. Alberta) Colloquium

10 Nov 2025, 08:30 → 11 Nov 2025, 15:15 US/Eastern

https://sites.ualberta.ca/~jdavis/

Davis Lab research focuses on large scale quantum objects, in particular nanomechanical objects at low temperatures and superfluids in restricted geometries.  This work combines precision nanofabrication, cryogenics, optomechanics, and quantum measurement protocols.  We are also interested in putting these devices to good use, especially in future quantum technologies

Monday 10 November

1 Pickup at Cumberland House and travel to campus

Speaker: Prof. Adrian Del Maestro (University of Tennessee, Knoxville)

2 Meeting with UTK Physics & Astronomy Faculty

Speaker: Prof. Adrian Del Maestro (University of Tennessee, Knoxville)

3 Meeting with UTK Physics & Astronomy Faculty

Speaker: Michael Guidry

4 Meeting with UTK Physics & Astronomy Faculty

Email and Work time

5 Meeting with UTK Physics & Astronomy Faculty

Dien Nguyen

6 Meeting with UTK Physics & Astronomy Faculty

Rpbert Grzywacz

7 Lunch

Speaker: Prof. Adrian Del Maestro (University of Tennessee, Knoxville)

8 Meeting with UTK Physics & Astronomy Faculty

Speaker: Wonhee Ko (University of Tennessee, Knoxville)

9 Meeting with UTK Physics & Astronomy Faculty

Speaker: Lucas Platter

10 Meeting with UTK Physics & Astronomy Faculty

Speaker: Dr Kostya Nasyedkin (ORNL)

11 Pre-Colloquium Reception

12 Colloquium: Sensing Gravitational Waves and Dark Matter with Superfluid Helium

Observations spanning multiple astronomical scales point to the existence of an unknown form of matter, dubbed “dark matter”, that constitutes over 85% of the mass of most galaxies. Recent theoretical insights into the possible nature of dark matter and how it interacts with normal matter have inspired a wide range of experimental efforts aimed at directly detecting dark matter. As part of this effort, we are developing a small-scale experiment to search for multiple well-motivated “ultralight” dark matter candidates, placing stronger bounds than are currently possible with high-cost and/or large-scale efforts. The core enabling technology relies on microwave cavity readout of mechanical motion in superfluid helium. I will tell you about the experiments that have led up to where we are now, and our current efforts with regards to this table-top dark matter search.

Speaker: Prof. John Davis (Univ. Alberta)

17:00 Break and Return to Hotel

18:00 Dinner

Tuesday 11 November

13 Pickup at Hotel and Travel to IAMM

Speaker: Prof. Adrian Del Maestro (University of Tennessee, Knoxville)

14 Research Discussion

15 Research Discussion -Alan Tennant IAMM 309

Speaker: Alan Tennant

16 Research Discussion

Speaker: Prof. Adrian Del Maestro (University of Tennessee, Knoxville)

17 Research Discussion

Speaker: Prof. Adrian Del Maestro (University of Tennessee, Knoxville)

18 Research Discussion

Speaker: Tony Mezzacappa

11:30 Lunch

19 Zero Point Cryogenics

In general, quantum technologies must be operated in the sub 1 K regime, a demanding area of cryogenics. In fact, the technologies to reach below 1 K with continuous operation are few and far between, and therefore the dilution refrigerator, capable of continuous operation in the mK regime is often the preferred choice. I will begin by reviewing the principles of operation of a dilution refrigerator, and tell you about some of the advances in dilution refrigerator technology that we have made at Zero Point Cryogenics. Following this, I will describe our new, patent-pending technology that we call the phase separation refrigerator. It allows continuous operation below 500 mK, with very fast start-up and minimal 3He usage. We believe this will find significant applications in the future of quantum technologies.

Speaker: Prof. John Davis (Univ. Alberta)

20 Research Discussion

Speaker: Yang Zhang

21 Research Discussion

ULT-STM Lab tour

Speaker: Wonhee Ko (University of Tennessee, Knoxville)

22 Depart for Airport