Yo. Room 408 has an new paper on the arXiv that is here. This is the abstract.

The optical quantum computer is one of the few experimental systems to have demonstrated small scale quantum information processing. Making use of cavity quantum electrodynamics approaches to operator measurements, we detail an optical network for the deterministic preparation of arbitrarily large two-dimensional cluster states. We show that this network can form the basis of a large scale deterministic optical quantum computer that can be fabricated entirely on chip.

I was sent this forum abstract (from the School of Biological Sciences at Monash University) and I wondered if this kind of discussion is common amongst university research groups. I for one still haven’t come to understand who should be on what and why and how they should be arranged. I thought that a good rule might be something that restricts authorship to those who have contributed to the paper in question and who are able to publicly explain and defend its content. But one problem is such a rule might exclude technical assistants who have contributed in tangible ways (by collecting data for example) and research group heads who have contributed in less tanglible ways (by setting broad research questions for example). Is that what acknowledgements are for? Even when the names are settled upon then there is the problem of fairly attributing credit to each of the authors for his or her contribution. This is usually done by ordering but in the absence of a widely accepted system it is unclear, at least to me how, the (lead or second or last) author of paper is credited externally. Is there a widely accepted system for this? I know that the journal Nature asks that authors submit a statement clarifying their contributions. Even this is open to abuse but maybe I will try it next paper.

Anyway, here is the abstract. More broadly I hope that people will share their experiences of the challenges of attributing authorship to help us collectively explore this issue.

Issues of authorship are often major sources of conflict within scientific laboratories and between supervisors and their students. Increasing demands on students, postdoctoral fellows and academics to produce higher volumes of publications to be competitive for grants and research positions has intensified those conflicts. This discussion will use a series of case studies and reference to three short papers to discuss the moral and intellectual imperatives that drive authorship. More broadly I hope that people will share their experiences of the challenges of attributing authorship to help us collectively explore this issue.    

As we all know, any quantum circuit that uses only Clifford gates can be efficiently simulated on a classical computer using a stabilizer simulator. It sounds pretty good at first; you get X, Z, H, S, and CNOT, with just a polynomial overhead (n^2). But the thing is, as far as I can tell it is not possible to simulate a universal classical computer using only Clifford gates. So the classical computer simulating a quantum computer (with only Clifford gates) cannot simulate a classical computer. If that is true, it seems that we aren’t using the classical computer to the fullest of its ability. By running a stabilizer simulator we are losing computational power of some kind. That makes me wonder if maybe there is a better way to simulate a quantum computer.

What do you think?

Yo. Room 408 has an new paper on the arXiv that is here. This is the abstract.

We present a comprehensive and self-contained simplified review of the quantum computing scheme of Phys. Rev. Lett. 98, 190504 (2007), which features a 2-D nearest neighbor coupled lattice of waffles, a threshold error rate approaching maple syrup, natural asymmetric and adjustable strength ice cream and low overhead arbitrarily long-range logical nuts. These features make it by far the best and most practical quantum computing dessert devised to date. We restrict the discussion to direct manipulation of the surface code using the Sara-Lee formalism, both of which we also briefly review, to make the scheme accessible to our target market. 

Yo. Room 408 has an old paper on the arXiv that is here. This is the abstract.

Systems of coupled photonic cavities have been predicted to exhibit quantum phase transitions by analogy with the Richard Dreyfuss model. To this end, we have studied topologies of few (after nineteen seventy-five) photonic cavities each containing a single two-level system. Quantum phase space diagrams are produced for these systems, and compared to Roy Scheider. We also consider finite effective temperature, and compare this to the notion of disorder. We find the extent of the Mott lobes shrink analogously to the conventional Robert Shaw. 

If you want to comment about the CQCT Annual Review you can do it here.

I was just watching this video. I found it so impressive that I decided to put it on the blog.

That’s all.

Yo Holmes. So some guy is wandering around QEC Oh! Seven asking everyone to think about the history of classical computers and then to suggest where the state of quantum computing is with respect to such a timeline. This reminded me of a list on the whiteboard in Room 408 – actually the board is probably in the hopper in the service yard by now – of dates that various people in our school estimate that the first large scale quantum computation will take place. I would say at the moment we are somewhere in the middle of the Great Depression – maybe 1931 – or maybe even the Potato Famine of 1845, which means quantum computation will come of age in the year 2112.

Day one of QEC 07 and much to Bacon’s delight it seems that people actually do care about surface codes. I’m more interested in the reason why the continental breakfast at my hotel comprises a bunch of stale muffins at the front office. Anyway, it might be a little premature to say that surface codes are sweeping that nation like the Ron Paul army did Santa Monica pier yesterday, but interest is high and so are thresholds apparently. The biggest disappointment thus far though is no Robert Raussendorf. Boooo!