Artsey fridge pics

Here are some artsey pictures of the latest incarnation of the fridge and it’s related experiments. I love wires 🙂

I’ve been putting on some additional equipment to do differential conductance measurements, to look at the effect of materials with interesting densities of states on the IV curves. The wiring won’t stay so messy for long, I just thought I’d get some pictures whilst it all looks a bit Alien.



This is a different fridge, it’s an Adiabatic Demagnetisation Refrigerator. I have been recently setting up an experiment on this one, although I might move it back to my original fridge to save liquid Helium (this thing eats 175L in one go!)

5 thoughts on “Artsey fridge pics

  1. quantummoxie says:

    Ooo, interesting (so said the theorist right before he pressed the button clearly labeled “do not press”). Seriously, what exactly does it do again?

  2. physicsandcake says:

    At the moment I’m doing Macroscopic Quantum Tunneling experiments and Macroscopic Resonant Tunneling (microwave activation) experiments on Josephson Junctions (operating as phase qubits). I’m looking at the switching distributions of the critical current of a Josephson Junction, where below a certain temperature escape events are dominated by quantum tunneling processes. As we’re planning on fabricating and measuring qubits, we need to make sure that they are operating in the quantum regime and are not dominated by thermal activation or noise-driven escape from the washboard potential. This has been done lots of times before for low Tc and some High Tc junctions, we’re reproducing these results to show our system works properly and then moving onto some more novel types of junctions.

    We’re also investigating the effect of dissipation on the MQT and hopefully (eventually) on the coherence times, by measuring Rabi oscillations.

    Hope that all makes sense!

    There actually IS a button that I had to label ‘do not press’ or rather it says ‘THINK BEFORE OPENING THIS VALVE!!’ because it connects 2 parts of the vacuum system through a slightly obscure route and you can easily end up losing your 3He-4He mixture this way (not a good idea…)

  3. quantummoxie says:

    Aha, smart thinking in case any theorists enter the room. Anyway, your work sounds pretty cool. I met another guy recently working with Josephson Junctions (he’s at Colgate University but I can’t remember his name).

    So, in essence, by looking at the critical current you’re looking to identify about where the quantum/classical border is (which is way cool). Identifying that border is something I’ve been very interested in for awhile, particularly in its relation to statistical mechanics.

  4. physicsandcake says:

    I think I know who you mean now – Kenneth Segall. I happened to be reading a couple of his preprints on Arxiv the other day and remembered 🙂 Yes, they do some cool stuff, work with qubits and Macroscopic Quantum Tunneling in Niobium Josephson rings.

  5. quantummoxie says:

    Yeah, I think that’s him. I gave a talk at Colgate this spring and met a bunch of faculty which is why I know him.

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