P&C on Twitter

Physics and Cake now has a twitter feed:

check out @physicsandcake on Twitter!

I won’t be neglecting the blog, but twitter seems more useful for posting links as you find them. It stops them from clogging up my bookmarks folder!


A fridge by any other name…

So my dilution refrigerator is nicknamed Frosty. In addition to being a neat acronym (FRidge Of Substantially Tempramental Yield) the name is somewhat more grounded in one of his physical attributes, i.e. that of being rather inefficient at keeping the cold where it should be 🙂 It’s really important to remember not to touch the fridge when it’s like this. Your fingers end up stuck to the thing and you can take off several layers of skin if you’re not careful.



Yes, that is an icicle on the safety overpressure valve. No, it shouldn’t be there…

Coffeebreak Links 200809

Everything’s been so busy this past week, I’ve got a whole load of links and they’re all completely disorganised, but here are a few just so I a get them off the backlog pile:

A really interesting company I learnt about recently:
Evolved Machines

Upcoming Events

World Future Society conference 8-10 July 2010, Massachusetts
World Future 2010

SENS4 Conference in Cambridge, UK 4-7 Sept 2009

and From the RI events calendar:
A brain for life: The 21st century mind Friday 25 September 2009

This one looked good too:
September09 Cafe Scientifique: Quantum mechanics Monday 21 September 2009
but it’s fully booked now. It might be worth calling them a couple of days before to see if there are any cancellations.

If Quantum-themed cafe scientifiques are this popular, I might see if I can get one arranged for Birmingham and get some guest speakers in 🙂

Fun and educational videos:

This is awesome:
Scott Aaronson vs. Eliezer Yudkowsky on BloggingHeads TV
Great if you love argumentss about Many-Worlds.

A video feed dedicated to Electronic Engeneering! Brilliant stuff:
Electronics Engineering Video Blog Podcast

Singularity University 2009

I’ve been spending the last few days hanging around at Singularity University hosted at NASA Ames in Mountain View, CA (SIlicon Valley).

Singularity University Flag Logo

What an experience. The people here are great, real leaders and entrepreneurs. It’s been inspiring to talk to everyone. The format of the course is several weeks of lectures and presentations by distinguished speakers, site visits to companies and R&D labs, followed by several weeks where the students focus on their team projects, with a view to ‘Changing the lives of a billion people’. Several of the team projects are expected to flourish into companies continuing well after SU 2009 has finished.

The course takes place at the same time and place as the International Space University, so there is even more opportunity for networking with like-minded people. In fact SU was modelled on the successful courses that ISU has been running for 20 years.

I’ve mainly been talking to people about quantum computing and future quantum technologies. Everyone has been very receptive and the discussions have been heated and immersive. We’ve talked about everything from uploading to teleportation, and from solving world poverty to finding personal happiness. I’ve also met lots of fellow Singularitarians, and some fellow Transhumanists, which has also helped spark interesting conversation. It’s quite easy to sometimes feel the Loneliness of the Singularitarian scenario that Ray Kurzweil describes, but places like this make you realise that progress IS being made and that there ARE people who share your views, dreams, and goals.

One thing I’ve also learnt here is that people value art, creativity and entertainment as highly as business, tech and hard science. Silicon Valley defintely has a ‘Work hard, Play hard’ mentality. I’m hoping I can take some of these skills back and use them in the somewhat more restrained and introvert world of academic research.

Qudos on the Qudits!

Martinis group at UCSB have demonstrated operations on a quantum bit with 5 levels (qudit with d=5) instead of the usual 2 (qubit):

“Emulation of a Quantum Spin with a Superconducting Phase Qudit”
Matthew Neeley,1 Markus Ansmann,1 Radoslaw C. Bialczak,1 Max Hofheinz,1 Erik Lucero,1 Aaron D. O’Connell,1 Daniel Sank,1 Haohua Wang,1 James Wenner,1 Andrew N. Cleland,1 Michael R. Geller,2 John M. Martinis1,

They use a standard type of phase qubit experiment in which the quantum states are defiined by a ladder of energy levels in a single potential well, rather than the more common flux qubit where the energy levels arise from the degeneracy between two adjacent wells. The qubits/qudits are controlled by applying very careful timed and shaped pulses of microwaves to excite the quantum states between levels and to allow the levels to interact with one another. The energy between each level is very slightly different due to the anharmonicity of the Josephson junction’s energy landscape, so each level transition has a unique ‘frequency signature’. (This scheme wouldn’t work if the quantum states were in a harmonic oscillator, as all the levels would be equally spaced.)

The group demonstrate a shift in the Ramsey fringes which equates to the expected Berry phase produced by the rotation of the quantum state around the Bloch Sphere. They also demonstrate robust Rabi oscillations and the swapping of quantum information between states. The relaxation times of the states are all in the 100’s of ns, but are smaller for the higher states.

I can’t really stress how exciting this result is for experimental quantum computation with superconducting circuits – it opens up new possibilities for implementation of algorithms and quantum simulation. The group focus on the potential of the technique for emulating quantum spin systems.

I wonder what algorithms have been developed that require multi-dimensional Hilbert spaces for their implementation? I know that higher dimensional quantum bits can help make quantum cryptography more secure. I find a sudden renewed interest in learning about qudits…

I’m also slightly smug in my opinion that this once again puts Josephson SC qubits marginally ahead in the awesomeness stakes. (Those ion trap guys were really giving us a run for our money). Qutrit systems (3 levels) have been realised in NMR and Ion trap QC but I believe that experiments like this really open up the door for more complex QIP realizations.


As much as I admire some of the traditonal values of Oxbridge/Ivy league style University education, I can’t help but love the idea of this new movement…

Via Academic Earth:

Who needs Harvard? How Web-Savvy Edupunks Are Transforming American Higher Education

Who’d have thought education and anarchy would join forces? 🙂

I’m going to have to put together a lengthy list of online resources for this kind of thing at some point. Although there’s plenty of raw material about, I don’t think there’s enough stuff about learning how to learn via this DIY method. That’s why we’ll still continue to pay vast amounts for education, it’s about the framework and technique more than the raw information. I’m currently trying to write something approaching a coherent article/essay about some of these ideas.

Argh – another ‘I’ll write a post’ post – I suck.