Theorists use cloud-based Bose–Einstein condensate to study tunnelling

WEBVTT
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- Hello, and welcome to the Physics World weekly
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- podcast. I'm Hamish Johnston.
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- I'm very pleased to be joined from Japan
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- by two theoretical
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- physicists.
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- They are Ippei Danshita
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- of Kindai University
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- and Daichi
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- Kagemihara
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- at Chuo University.
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- They led a team who have gained important
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- insights into quantum mechanical tunneling
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- by doing remotely controlled experiments
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- on a Bose Einstein
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- condensate
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- that was located more than 8,000
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- kilometers away
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- in The US.
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- In our conversation,
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- Daichi and Ipe talk about the challenges
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- of making measurements using an apparatus
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- on the other side of the world.
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- And they also reveal what they've learned,
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- both about the physics of tunneling
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- and about how remote experiments
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- can help theorists
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- test their calculations.
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- The BEC platform they used is called Octant,
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- and it was created and operated
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- by the quantum
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- technology company
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- Inflexion
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- as Daichi explains.
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- Hi, Ibe and Daichi.
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- Welcome to the podcast.
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- Hi, Hamish.
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- Thank you very much for the invitation.
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- Hi, Hamish. Yeah. I'm Oren too.
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- Well, that's great. I'd like to thank both
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- of you for joining me today. It's... We're
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- we're recording this on a Friday afternoon,
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- and I think it's... What time is it
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- in Japan? Is it 04:30 or maybe 05:30?
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- So thanks thanks so much to you for,
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- for joining me so late in the day,
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- late in the week.
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- My first question is to,
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- Daichi.
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- You've used Inflexion's
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- Octant cloud based Bose Einstein condensate
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- for your research.
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- Can you describe
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- Octant? What
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- what does the system,
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- what does it comprise of?
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- Yeah. Octant is
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- a cloud based experimental platform,
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- that allows us to remotely perform experiment with
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- bose Einstein condensates,
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- BG.
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- Users
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- can submit
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- experimental protocols,
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- through a web interface
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- or for advanced controls using Python.
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- Obtained then carries out experiments,
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- and return measures data for analysis.
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- Octant provide two
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- experiments,
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- the preparation of BC and
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- the manipulation of its dynamics.
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- In the preparation part,
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- atoms,
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- atoms,
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- cooled down by so called evaporative
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- cooling.
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- We can
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- design this cooling schedule.
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- This allow us
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- to control the property of the prepared BC,
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- such as
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- temperature and on the set fractions.
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- The second type of experiment is to,
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- manipulate the BC in
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- in a harmonic trap. We can apply,
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- we can apply especially,
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- temporary varying potentials to drive
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- the dynamics of BC.
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- We also...
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- We can also take
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- images corresponding to the atomic density
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- by repeating
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- experiment with the same,
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- potential schedule,
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- while changing
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- the imaging time. We can study the real
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- time evolution
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- of the BC.
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- This is,
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- this is essentially what we did in our
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- research in in this... In our paper.
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- Aniopei, there's there's one thing that I've wondered
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- about this this remote control
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- BEC. Is there actually somebody there,
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- you know, at inflection,
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- twiddling the knobs for you? I mean, are
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- you telling somebody to set the experiment up,
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- and there's an actual person there?
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- Or is it all done,
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- you know, remotely,
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- if you see what I mean, with no
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- person involved,
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- at the actual
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- vacuum chamber with the BEC?
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- Yeah. That's actually a very good question, but
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- we
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- actually have never asked
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- the,
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- administrator
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- or this, experimental equipment.
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- So... But we we... Our guess is that,
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- well, things are automated,
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- actually.
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- But,
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- someone,
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- in charge of this experimental experiment
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- is there during the...
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- So during the,
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- time slot where we can do the experiment.
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- The...
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- I think so because
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- the... There is kinda limited time slot for
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- operating the octant, and this is actually business
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- time of The United States.
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- Mhmm. That's... Yeah.
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- That's how we see here.
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- I see. And and, Ipe, what are the
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- benefits
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- of doing
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- BEC
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- experiments remotely?
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- I mean, I suppose the obvious benefit is
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- that you don't have to
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- have, you know, what is a fairly
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- expensive
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- vacuum system,
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- an optical system. But, I mean, could could
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- could you talk about that? And and also
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- maybe, you know, the other benefits of using
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- the system. Yeah. So let me explain. So,
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- of course, yeah, as I said, it's a
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- kinda... Main benefit is, you know, our,
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- theoretical physicist like us can use it without,
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- I mean, building up the experiment from scratch.
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- That's the... Actually, the big benefit.
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- But I also want to say that, you
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- know, the traditional way
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- for the theoretical physicist
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- to access to the experimental facility
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- is usually to collaborate
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- with
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- experimenters.
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- Yeah? So from time time from time to
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- time, I actually had such fortunate opportunities
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- to collaborate with,
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- excellent experimenters, which I really enjoyed, actually.
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- However,
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- the initiative
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- of such collaboration is mainly taken by the
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- PI or the experimental group. So the suggestions
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- by terrorists are accepted only sometimes.
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- So that mean
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- take... So being able to take the initiative
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- of the experimental research is a big advantage
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- and a big benefit of using such kind
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- of platform. So for example, the... About twenty
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- years ago,
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- I theoretically worked on the anomaly standard or
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- the phonon or BC
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- and talked with several experimentalists
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- about possible experimental realization
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- of this interesting phenomenon.
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- Unfortunately,
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- there were no experimentalists
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- who actually conducted such experiments.
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- So twenty years later, we could observe such
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- signatures of this unknown standard
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- by using remote PC strength service, this octant.
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- So I think that this indeed demonstrates
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- the benefits of octant.
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- So, Ipe, does that mean, as a theorist,
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- you feel closer
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- to the experiment?
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- You know, maybe in the past when you
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- you you weren't actually controlling a BEC,
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- the, you know, the whole system seemed a
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- bit foreign and away from your work. But
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- now that you... You're almost hands on,
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- do do, you know, do you feel that
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- you have more insights into the physical system
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- using Octant?
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- Yeah. Of course. I mean, the real system
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- is much dirtier than the theory.
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- Right?
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- So... Yeah.
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- I mean, you have to take care of
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- the noise or, you know, some
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- calibration stuff also. So, yeah, we...
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- I mean,
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- in in that sense, we are closer to
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- the, I mean,
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- the reality.
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- So
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- that, how to say? The... But, actually, honestly,
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- I have... As I said, the... I have
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- collaborated,
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- several experiences before. In that sense, you know,
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- I already have some close... I I feel
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- that very close to this
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- system.
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- But, yeah, but, you know, the... In the
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- collaboration with the experimenters, usually,
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- experimenters take care of this kind of dirty
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- environment
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- in the experiment. So
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- we... I actually learned
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- how the... How great the syringe is actually.
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- They they are kinda...
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- They have this kind of... Yeah. Yeah. That...
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- I mean, the ability to get a very
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- clear physics. Yes. Interesting. And have you been...
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- I mean, in your experience using Octant, have
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- you been tempted
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- to maybe do some experimental work, or do
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- you think that you're always going to be
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- a theorist? I I mean, can you see
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- yourself working in a lab? I suppose you
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- don't have to, but... Yeah. To be honest,
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- I'm
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- happy to be a theorist. I mean...
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- Yeah. Yeah. I don't know. That that can
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- be the physics world quote of the week.
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- I'm happy to be a theorist.
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- Yeah. Definitely. It's, yeah. I I just think
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- that the experimenters are so great because they
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- can... Are very patient
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- to fight with those kind of... Yeah. They're...
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- I mean, that reality.
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- And and, Daichi, we've we've spoken about some
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- positive aspects
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- of doing
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- remote experiments
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- on BECs.
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- Are there any negative
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- aspects
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- to doing remote experiments?
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- One thing,
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- we have to keep in mind
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- was,
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- remote users still
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- carefully characterize the parameters of the apparatus and
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- the initial state of the BC. So for
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- example,
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- we initially assume that
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- the prepared BC is stationary.
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- But in fact, the prepared BC
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- was undergoing
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- a small dipole oscillation.
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- Yeah. This is
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- this is because,
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- BC first prepared in a cooling trap and
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- then transferred to imaging trap.
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- And the,
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- trap center... Two trap centers
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- are not perfectly aligned.
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- For this reason, we first apply,
277
00:11:00.959 --> 00:11:02.419
- linear potential to
278
00:11:03.279 --> 00:11:05.459
- to reduce this initial motion,
279
00:11:06.240 --> 00:11:07.539
- yeah, in our experiment.
280
00:11:08.079 --> 00:11:09.279
- We also found that,
281
00:11:10.799 --> 00:11:14.399
- some parameters... Some experimental parameters to lift it
282
00:11:14.399 --> 00:11:15.139
- over time.
283
00:11:15.975 --> 00:11:16.634
- For example,
284
00:11:17.414 --> 00:11:17.975
- we found,
285
00:11:18.774 --> 00:11:20.235
- the center of a trap,
286
00:11:20.695 --> 00:11:21.754
- yeah, could change,
287
00:11:22.454 --> 00:11:24.235
- from week to week. So
288
00:11:25.095 --> 00:11:25.595
- so,
289
00:11:26.134 --> 00:11:28.794
- at the beginning of each experimental periods,
290
00:11:29.259 --> 00:11:30.240
- we first measure
291
00:11:30.620 --> 00:11:31.120
- the
292
00:11:31.579 --> 00:11:35.500
- the dipoles... Yes. Affirmation dipole oscillation and estimate
293
00:11:35.500 --> 00:11:38.159
- the trap of... Trap center from,
294
00:11:39.100 --> 00:11:39.919
- from that
295
00:11:40.379 --> 00:11:41.199
- that motion.
296
00:11:41.500 --> 00:11:43.304
- Yeah. And, yeah, we correct
297
00:11:44.424 --> 00:11:46.445
- our ex... Experimental schedule,
298
00:11:47.225 --> 00:11:48.605
- yeah, from estimates,
299
00:11:50.105 --> 00:11:50.924
- top center.
300
00:11:51.464 --> 00:11:52.284
- So overall,
301
00:11:53.464 --> 00:11:55.804
- even using a remote experimental platform,
302
00:11:56.664 --> 00:11:57.245
- we still
303
00:11:59.230 --> 00:11:59.730
- carefully
304
00:12:00.590 --> 00:12:01.090
- carefully
305
00:12:01.629 --> 00:12:03.730
- characterize the experimental parameters
306
00:12:04.990 --> 00:12:06.049
- and correct for...
307
00:12:08.029 --> 00:12:11.149
- And what did the effect before the... If
308
00:12:11.149 --> 00:12:13.235
- you are carrying out the main
309
00:12:13.774 --> 00:12:14.274
- experiment.
310
00:12:14.735 --> 00:12:17.934
- I see. And and, Ipi, is that... Is
311
00:12:17.934 --> 00:12:21.154
- the problem here the fact that you're using
312
00:12:21.214 --> 00:12:22.434
- a a generic
313
00:12:23.294 --> 00:12:24.115
- Bose Einstein,
314
00:12:25.470 --> 00:12:26.690
- experimental apparatus.
315
00:12:27.389 --> 00:12:30.509
- And if if you, you know, you know,
316
00:12:30.509 --> 00:12:32.290
- let's say you were doing this experiment,
317
00:12:33.230 --> 00:12:35.169
- you know, on your own in the lab,
318
00:12:35.470 --> 00:12:38.049
- you would have designed an apparatus where this
319
00:12:38.110 --> 00:12:39.330
- back and forth motion
320
00:12:40.334 --> 00:12:42.815
- was not a problem or could be more
321
00:12:42.815 --> 00:12:44.894
- easily dealt with? I mean, I suppose my
322
00:12:44.894 --> 00:12:46.574
- question is, you know, is the issue here
323
00:12:46.574 --> 00:12:48.514
- that you... You're trying to do a specific
324
00:12:49.054 --> 00:12:52.495
- experiment on a a system? Yeah. Definitely. If
325
00:12:52.495 --> 00:12:52.995
- you,
326
00:12:53.889 --> 00:12:55.190
- I mean, if you
327
00:12:56.209 --> 00:12:59.350
- have such kind of system in your lab,
328
00:12:59.490 --> 00:13:00.629
- you could easily
329
00:13:01.009 --> 00:13:04.289
- realize that, the motion should happen because the...
330
00:13:04.289 --> 00:13:05.990
- In the... What... After
331
00:13:06.370 --> 00:13:07.965
- we recognize that the
332
00:13:08.764 --> 00:13:09.904
- the trap for cooling
333
00:13:10.524 --> 00:13:11.345
- of the BC
334
00:13:11.805 --> 00:13:13.345
- and the trap for the,
335
00:13:14.845 --> 00:13:15.665
- laser manipulation
336
00:13:16.125 --> 00:13:19.665
- seeing this, for observing the BC dynamics.
337
00:13:20.045 --> 00:13:21.965
- So those two are actually different traps. So
338
00:13:21.965 --> 00:13:23.504
- they they actually transfer
339
00:13:23.809 --> 00:13:26.230
- the BC from one trap to the another.
340
00:13:26.449 --> 00:13:28.230
- But we actually didn't know.
341
00:13:28.610 --> 00:13:31.649
- So if you transfer the BC from one
342
00:13:31.649 --> 00:13:32.709
- trap to another,
343
00:13:33.329 --> 00:13:35.409
- it's very natural that you call this type
344
00:13:35.409 --> 00:13:38.184
- of oscillation. Right? So if you build up
345
00:13:38.184 --> 00:13:40.605
- the system by yourself, you should know it.
346
00:13:42.024 --> 00:13:44.204
- Yeah. But, we didn't know because we didn't
347
00:13:44.504 --> 00:13:47.464
- build up the system by ourselves. I see.
348
00:13:47.464 --> 00:13:48.524
- Okay. Gotcha.
349
00:13:49.460 --> 00:13:50.840
- And, and Ipe,
350
00:13:51.860 --> 00:13:55.000
- in in a recent paper, you explored phonon
351
00:13:55.139 --> 00:13:55.639
- tunneling
352
00:13:56.100 --> 00:13:57.080
- in a BEC.
353
00:13:58.580 --> 00:14:00.660
- What what is phonon tunneling? And can can
354
00:14:00.660 --> 00:14:02.920
- you describe the measurements that you made?
355
00:14:03.940 --> 00:14:04.274
- Yes.
356
00:14:04.835 --> 00:14:08.215
- Let me first briefly explain the anomalous tunneling
357
00:14:08.514 --> 00:14:11.315
- of the phonon in BC, which is a
358
00:14:11.315 --> 00:14:13.254
- important protein of this, phonon
359
00:14:13.795 --> 00:14:14.295
- tunneling.
360
00:14:15.154 --> 00:14:18.299
- So in a conventional quantum tunneling, like the
361
00:14:18.299 --> 00:14:21.519
- case of, non interacting electrons or atoms,
362
00:14:22.059 --> 00:14:25.100
- when you decrease the energy of the quantum
363
00:14:25.100 --> 00:14:25.600
- particle,
364
00:14:26.299 --> 00:14:28.720
- the transmission probability actually decreases
365
00:14:29.340 --> 00:14:31.485
- and approaches zero at
366
00:14:31.964 --> 00:14:34.605
- limit of zero energy. I mean, the low
367
00:14:34.605 --> 00:14:35.584
- energy particle
368
00:14:36.204 --> 00:14:38.464
- hardly handles through a barrier.
369
00:14:39.884 --> 00:14:42.764
- By contrast, in the case of phonons in
370
00:14:42.764 --> 00:14:43.264
- BC,
371
00:14:43.804 --> 00:14:45.664
- the tendency is actually opposite.
372
00:14:46.169 --> 00:14:47.870
- I mean, when you decrease
373
00:14:48.250 --> 00:14:48.909
- the energy,
374
00:14:49.450 --> 00:14:53.789
- the transmission probability actually increases and approaches unity
375
00:14:54.169 --> 00:14:55.549
- at zero energy limit.
376
00:14:56.490 --> 00:14:58.669
- So the low energy phonons exhibit
377
00:14:59.129 --> 00:15:00.190
- almost perfect
378
00:15:00.674 --> 00:15:01.174
- tunneling.
379
00:15:01.794 --> 00:15:02.615
- That's the
380
00:15:03.235 --> 00:15:04.375
- anomalous tunneling.
381
00:15:05.475 --> 00:15:09.235
- So since this interesting phenomenon has never been
382
00:15:09.235 --> 00:15:09.735
- observed,
383
00:15:10.674 --> 00:15:12.134
- in experiments before,
384
00:15:13.049 --> 00:15:16.909
- We aim to experimentally observe it by using
385
00:15:17.129 --> 00:15:17.529
- this,
386
00:15:18.090 --> 00:15:19.389
- remote BC platform
387
00:15:20.090 --> 00:15:20.590
- octant.
388
00:15:21.370 --> 00:15:22.909
- As a specific protocol,
389
00:15:23.210 --> 00:15:26.009
- we actually first part of the BC in
390
00:15:26.009 --> 00:15:28.654
- a double trap. Double trap mean that the
391
00:15:28.654 --> 00:15:29.634
- trap plus,
392
00:15:30.415 --> 00:15:32.434
- barrier potential at the trap center.
393
00:15:33.615 --> 00:15:34.115
- So...
394
00:15:34.415 --> 00:15:37.054
- And the... This part of patient to the
395
00:15:37.054 --> 00:15:39.075
- BC actually induce the corrective
396
00:15:39.455 --> 00:15:39.955
- oscillation
397
00:15:40.495 --> 00:15:41.795
- of the BC.
398
00:15:42.550 --> 00:15:45.670
- And from the observed oscillation, we actually measure
399
00:15:45.670 --> 00:15:47.450
- this oscillation. And from the
400
00:15:47.990 --> 00:15:48.970
- observed oscillation,
401
00:15:49.590 --> 00:15:51.290
- we could extract
402
00:15:52.149 --> 00:15:52.649
- frequencies
403
00:15:53.190 --> 00:15:56.389
- of the collective oscillation modes for several values
404
00:15:56.389 --> 00:15:57.610
- of the barrier height.
405
00:15:58.115 --> 00:16:01.315
- So we find that the quality modes with
406
00:16:01.315 --> 00:16:01.815
- relatively
407
00:16:02.274 --> 00:16:03.095
- low frequencies
408
00:16:03.714 --> 00:16:05.254
- are not very much affected
409
00:16:05.794 --> 00:16:07.414
- by a high barrier.
410
00:16:08.034 --> 00:16:10.434
- This means that the potential barrier is less
411
00:16:10.434 --> 00:16:10.934
- effective
412
00:16:12.059 --> 00:16:13.919
- to lower frequency modes.
413
00:16:14.539 --> 00:16:17.579
- So this measurement captures a signal, the animal
414
00:16:17.579 --> 00:16:18.079
- standing
415
00:16:18.539 --> 00:16:19.679
- of BC phonon.
416
00:16:20.779 --> 00:16:23.259
- I see. And and are there any,
417
00:16:24.459 --> 00:16:26.559
- well, for lack of a better word, practical
418
00:16:27.554 --> 00:16:30.274
- applications of this phonon tunneling effect? I mean,
419
00:16:30.274 --> 00:16:31.735
- is it something that could be
420
00:16:32.274 --> 00:16:34.375
- exploited in quantum computation
421
00:16:34.915 --> 00:16:36.215
- or quantum sensing?
422
00:16:36.915 --> 00:16:39.394
- Or is it is it just, well, just.
423
00:16:39.394 --> 00:16:41.815
- Is it a, you know, an interesting
424
00:16:42.500 --> 00:16:44.839
- phenomenon that needs to be understood?
425
00:16:46.179 --> 00:16:48.019
- Yeah. Yeah. That's good question. But,
426
00:16:48.659 --> 00:16:50.440
- no. I mean, we are
427
00:16:50.820 --> 00:16:51.559
- not very...
428
00:16:52.500 --> 00:16:53.159
- I mean,
429
00:16:54.100 --> 00:16:55.559
- have, any immediate
430
00:16:55.940 --> 00:16:57.480
- application of this phenomenon.
431
00:16:57.785 --> 00:17:00.445
- But this but, this phenomenon is,
432
00:17:01.345 --> 00:17:02.924
- what... At least, I believe,
433
00:17:03.384 --> 00:17:04.924
- important in two sense.
434
00:17:05.464 --> 00:17:07.945
- One is that, it is related to the
435
00:17:07.945 --> 00:17:10.825
- other interesting phenomenon of the BC, which is
436
00:17:10.825 --> 00:17:11.404
- a superfluidity.
437
00:17:12.340 --> 00:17:15.059
- Well, in my PhD work, actually, we... I
438
00:17:15.059 --> 00:17:15.559
- actually,
439
00:17:16.180 --> 00:17:19.160
- showed that, you know, anomalous tunneling property
440
00:17:19.700 --> 00:17:23.000
- is closely related to this b... Superfluid property
441
00:17:23.140 --> 00:17:25.460
- or the BEC. But it's very natural that
442
00:17:25.460 --> 00:17:27.000
- in the... So, you know, original,
443
00:17:28.285 --> 00:17:31.904
- famous Landau... Lev Landau's superfluid theory,
444
00:17:32.285 --> 00:17:33.184
- quasi particle
445
00:17:33.724 --> 00:17:35.345
- is included in the phonon excitation,
446
00:17:36.205 --> 00:17:37.664
- is the key to understand
447
00:17:38.205 --> 00:17:39.424
- the superfluid property.
448
00:17:40.150 --> 00:17:43.930
- The other thing is that, recent theoretical studies,
449
00:17:43.990 --> 00:17:46.089
- not not our work, actually
450
00:17:46.630 --> 00:17:48.569
- show that this anomalous standard
451
00:17:49.029 --> 00:17:50.809
- is, some universal
452
00:17:51.190 --> 00:17:53.450
- property of some condensed matter system
453
00:17:54.150 --> 00:17:54.650
- with
454
00:17:56.775 --> 00:18:00.394
- breaking... A spontaneous symmetry breaking or continuous symmetry.
455
00:18:00.535 --> 00:18:01.755
- I mean, the...
456
00:18:02.294 --> 00:18:03.115
- Something like,
457
00:18:04.535 --> 00:18:05.755
- some magnets,
458
00:18:06.214 --> 00:18:06.714
- antiferromagnet,
459
00:18:07.095 --> 00:18:08.794
- for example, a good example,
460
00:18:09.575 --> 00:18:10.710
- also exhibit
461
00:18:11.109 --> 00:18:13.849
- this unknown standing property. So it's a physicist
462
00:18:13.909 --> 00:18:16.089
- like this type of universal property.
463
00:18:16.869 --> 00:18:17.369
- Right?
464
00:18:17.990 --> 00:18:18.809
- We understand,
465
00:18:19.589 --> 00:18:20.089
- many
466
00:18:21.269 --> 00:18:23.450
- diverse system with single concept.
467
00:18:24.069 --> 00:18:26.565
- So... Well, of course, this formal excitation in
468
00:18:26.804 --> 00:18:29.684
- BC is character... Categorized as a number of
469
00:18:29.684 --> 00:18:30.504
- calls to mode.
470
00:18:31.365 --> 00:18:34.024
- So the recent study showed that this,
471
00:18:35.204 --> 00:18:38.744
- animal standing is actually the very universal property
472
00:18:38.804 --> 00:18:40.585
- of the number of calls to mode. So,
473
00:18:40.964 --> 00:18:42.089
- you know, this is that
474
00:18:42.650 --> 00:18:44.569
- how to say. I have to say not
475
00:18:44.569 --> 00:18:45.869
- application to the,
476
00:18:46.730 --> 00:18:47.630
- quantum technology,
477
00:18:48.169 --> 00:18:50.730
- but at least it's... You know? Yeah. We
478
00:18:50.730 --> 00:18:52.029
- are... As a physicist,
479
00:18:52.329 --> 00:18:54.250
- we should be very happy to fund this,
480
00:18:54.569 --> 00:18:57.815
- very universal property of this, this, number or
481
00:18:57.815 --> 00:18:59.234
- so more. And
482
00:19:00.414 --> 00:19:01.955
- and Daichi, you're you're
483
00:19:02.335 --> 00:19:02.835
- using
484
00:19:03.455 --> 00:19:06.595
- an experiment that's thousands of miles away.
485
00:19:07.695 --> 00:19:09.775
- You're in Japan, and I think the the
486
00:19:09.775 --> 00:19:11.875
- the apparatus is in The United States.
487
00:19:12.420 --> 00:19:14.759
- You weren't involved in building,
488
00:19:16.019 --> 00:19:18.180
- the experiments, and you're not sort of in
489
00:19:18.180 --> 00:19:21.000
- the room when the experiments are done.
490
00:19:21.380 --> 00:19:23.080
- How can you be confident
491
00:19:23.619 --> 00:19:26.039
- in the sort of experimental
492
00:19:26.420 --> 00:19:28.625
- parameters and data that
493
00:19:29.005 --> 00:19:30.865
- that you're being sent back?
494
00:19:32.365 --> 00:19:33.105
- You know,
495
00:19:33.404 --> 00:19:34.865
- how how do you know that the the
496
00:19:35.005 --> 00:19:36.224
- experiment is actually,
497
00:19:37.164 --> 00:19:39.325
- proceeding in the way that you think it
498
00:19:39.325 --> 00:19:41.984
- is? Yeah. That's a nice question. So
499
00:19:42.690 --> 00:19:44.149
- in in our experiment,
500
00:19:44.849 --> 00:19:46.149
- we try to verify
501
00:19:47.890 --> 00:19:49.109
- the experimental parameters
502
00:19:49.649 --> 00:19:50.549
- by comparing,
503
00:19:51.569 --> 00:19:54.230
- measurement result with theoretical expectations.
504
00:19:55.409 --> 00:19:56.390
- Yeah. For example,
505
00:19:57.250 --> 00:19:57.909
- the most
506
00:19:58.715 --> 00:19:59.914
- direct test was,
507
00:20:01.275 --> 00:20:02.095
- actual frequency.
508
00:20:03.515 --> 00:20:04.255
- Yeah. Atoms,
509
00:20:04.875 --> 00:20:05.775
- confined in
510
00:20:06.315 --> 00:20:09.515
- hammock trap, it's a collective center of mass
511
00:20:09.515 --> 00:20:10.015
- motion.
512
00:20:10.394 --> 00:20:10.894
- Sorry.
513
00:20:11.640 --> 00:20:14.839
- The frequency of the collective center of mass
514
00:20:14.839 --> 00:20:15.339
- motion
515
00:20:15.640 --> 00:20:16.299
- should be
516
00:20:16.920 --> 00:20:19.000
- the same as the trap center... A trap
517
00:20:19.000 --> 00:20:19.500
- frequency.
518
00:20:19.880 --> 00:20:21.420
- So, we measure
519
00:20:21.960 --> 00:20:23.900
- it and obtain approximately
520
00:20:24.200 --> 00:20:25.259
- 42 hertz
521
00:20:25.625 --> 00:20:26.125
- while
522
00:20:26.424 --> 00:20:27.485
- the Octane documentation
523
00:20:27.865 --> 00:20:29.085
- specifies the trap
524
00:20:29.625 --> 00:20:31.085
- frequency as 40 hertz.
525
00:20:31.705 --> 00:20:32.205
- So,
526
00:20:32.585 --> 00:20:33.565
- they are consistent.
527
00:20:34.025 --> 00:20:35.085
- We also perform
528
00:20:35.945 --> 00:20:37.164
- less direct consistency
529
00:20:37.465 --> 00:20:38.924
- check for other parameters.
530
00:20:39.580 --> 00:20:40.400
- As an example,
531
00:20:41.900 --> 00:20:42.559
- we checked
532
00:20:43.259 --> 00:20:44.160
- the transverse,
533
00:20:44.940 --> 00:20:45.840
- trap frequency,
534
00:20:46.700 --> 00:20:48.640
- from the frequency of,
535
00:20:49.580 --> 00:20:51.434
- second lowest collective motion.
536
00:20:51.835 --> 00:20:55.295
- We theoretically calculate the frequency of this mode
537
00:20:55.355 --> 00:20:55.855
- using
538
00:20:56.795 --> 00:20:58.255
- the transverse trap frequency
539
00:20:58.795 --> 00:21:01.134
- specified in the octant... Octant documentation,
540
00:21:01.755 --> 00:21:04.894
- and the calculated value was close to the
541
00:21:05.035 --> 00:21:05.940
- measured value.
542
00:21:06.819 --> 00:21:08.019
- So, yeah, we just,
543
00:21:08.500 --> 00:21:10.359
- did... You see, these are consistent.
544
00:21:10.819 --> 00:21:13.399
- Yeah. We performed as a consistency check,
545
00:21:14.740 --> 00:21:15.480
- as well,
546
00:21:15.859 --> 00:21:17.559
- for the parameters as well.
547
00:21:18.855 --> 00:21:20.875
- Overall, the quantity we
548
00:21:21.174 --> 00:21:21.994
- could check
549
00:21:23.255 --> 00:21:23.914
- were consistent,
550
00:21:25.654 --> 00:21:26.474
- with ex...
551
00:21:27.015 --> 00:21:29.994
- Doing experimental result with the theoretical expectations.
552
00:21:30.694 --> 00:21:32.474
- So this gave us
553
00:21:33.089 --> 00:21:35.669
- reasonable confidence in the experimental parameters
554
00:21:36.210 --> 00:21:38.690
- and data. Great. Well, it it sounds like
555
00:21:38.690 --> 00:21:40.390
- both of you are are happy
556
00:21:40.929 --> 00:21:41.410
- with,
557
00:21:42.130 --> 00:21:43.429
- with using Octant.
558
00:21:44.769 --> 00:21:47.089
- Are you are are you currently using the
559
00:21:47.089 --> 00:21:47.589
- system
560
00:21:47.934 --> 00:21:48.674
- to do,
561
00:21:50.174 --> 00:21:52.355
- cloud based BEC experiments,
562
00:21:52.894 --> 00:21:55.295
- IPE? Or do you have any plan for
563
00:21:55.295 --> 00:21:55.875
- the future?
564
00:21:56.734 --> 00:21:58.914
- Thank you for asking, actually. Currently,
565
00:21:59.455 --> 00:22:01.634
- we are not doing experiments on
566
00:22:02.000 --> 00:22:05.440
- Auckland platform just because Auckland has not been
567
00:22:05.440 --> 00:22:05.940
- open
568
00:22:06.240 --> 00:22:07.059
- to the public
569
00:22:07.680 --> 00:22:10.660
- since the late two thousand twenty four.
570
00:22:11.440 --> 00:22:14.259
- Well, for... They say it's for some upgrades.
571
00:22:15.875 --> 00:22:18.194
- So, however, yes, we have,
572
00:22:18.595 --> 00:22:20.115
- next brands of,
573
00:22:20.755 --> 00:22:22.375
- utilizing the for
574
00:22:22.914 --> 00:22:23.494
- the future.
575
00:22:24.355 --> 00:22:26.355
- But why... I cannot tell you too much
576
00:22:26.355 --> 00:22:27.734
- detail at this moment.
577
00:22:28.410 --> 00:22:31.630
- We have designed some of the future experiments
578
00:22:32.090 --> 00:22:35.289
- and made some, technical calculation for them. Yeah.
579
00:22:35.289 --> 00:22:37.049
- So we are kinda looking forward to the
580
00:22:37.049 --> 00:22:37.950
- next opening
581
00:22:38.570 --> 00:22:39.710
- of the octant.
582
00:22:42.164 --> 00:22:44.605
- Well, that's great. I hope, yeah. I I
583
00:22:44.605 --> 00:22:46.424
- I wish both of you luck in,
584
00:22:47.365 --> 00:22:49.684
- in in doing those experiments. And I'm guessing
585
00:22:49.684 --> 00:22:52.585
- you're you're probably very busy with your theory
586
00:22:52.804 --> 00:22:54.230
- work at the moment.
587
00:22:54.609 --> 00:22:56.450
- So it's not like you're you're sitting around
588
00:22:56.450 --> 00:22:57.509
- waiting for Octant
589
00:22:57.809 --> 00:23:00.130
- to come back online. But, I mean, it
590
00:23:00.130 --> 00:23:02.690
- sounds like you you you, you know, your
591
00:23:02.690 --> 00:23:04.289
- use of it was a was a great
592
00:23:04.289 --> 00:23:05.250
- success, and,
593
00:23:06.065 --> 00:23:07.744
- that they'd be very keen to get you
594
00:23:07.744 --> 00:23:08.244
- back
595
00:23:08.545 --> 00:23:09.684
- onto the system.
596
00:23:10.304 --> 00:23:12.545
- Daichi and Ipe, thank you so much for
597
00:23:12.545 --> 00:23:13.765
- coming on to the podcast
598
00:23:14.304 --> 00:23:16.964
- and talking to us about how you've used
599
00:23:17.265 --> 00:23:18.404
- a remote controlled
600
00:23:19.029 --> 00:23:20.410
- Bose Einstein condensate.
601
00:23:21.990 --> 00:23:24.390
- Yeah. Hamish, thank you very much. Yeah. Thank
602
00:23:24.390 --> 00:23:25.289
- you very much.
603
00:23:32.325 --> 00:23:35.704
- That was Ippei Danchita and Daichi Kagemihara
604
00:23:36.565 --> 00:23:38.265
- talking about their experience
605
00:23:38.644 --> 00:23:42.484
- of studying quantum tunneling while being thousands of
606
00:23:42.484 --> 00:23:44.424
- kilometers from the experimental
607
00:23:44.884 --> 00:23:45.384
- apparatus.
608
00:23:46.490 --> 00:23:48.490
- Thanks to both of them for joining me
609
00:23:48.490 --> 00:23:48.990
- today.
610
00:23:49.930 --> 00:23:51.710
- Their paper is called observation
611
00:23:52.090 --> 00:23:54.670
- of the influence of anomalous tunneling
612
00:23:55.130 --> 00:23:55.950
- on collective
613
00:23:56.410 --> 00:23:56.910
- excitations
614
00:23:57.850 --> 00:23:58.910
- via a cloud
615
00:23:59.210 --> 00:23:59.710
- experiment
616
00:24:00.090 --> 00:24:00.590
- platform
617
00:24:01.315 --> 00:24:03.095
- for Bose Einstein condensates,
618
00:24:03.955 --> 00:24:05.815
- and it's published in communications
619
00:24:06.275 --> 00:24:06.775
- physics.
620
00:24:07.555 --> 00:24:09.875
- I'll put a link to the paper in
621
00:24:09.875 --> 00:24:11.174
- the podcast notes.
622
00:24:11.795 --> 00:24:14.295
- If you enjoyed listening to today's podcast,
623
00:24:14.680 --> 00:24:17.500
- you'll find plenty more episodes to explore
624
00:24:17.880 --> 00:24:21.900
- at physicsworld.com/podcasts.
625
00:24:22.680 --> 00:24:26.119
- I'm Hamish Johnston, and our producer is Fred
626
00:24:26.119 --> 00:24:26.619
- Iles.
627
00:24:27.075 --> 00:24:29.794
- The music in our podcast is called one
628
00:24:29.794 --> 00:24:30.694
- three seven,
629
00:24:30.994 --> 00:24:33.714
- and it was composed and performed by the
630
00:24:33.714 --> 00:24:34.214
- physicist
631
00:24:34.595 --> 00:24:35.654
- Philip Moriarty.
632
00:24:36.595 --> 00:24:38.534
- We'll be back again next week.
633
00:24:38.835 --> 00:24:39.894
- Thanks for listening.