Seeing Quantum Simulators

From PhysicsWorld.com: Quantum simulators revealed in fresh detail. What I found the most interesting in the article:

"A Mott insulator with exactly one atom per lattice site represents a very promising candidate for a quantum register of up to a few hundred atomic quantum bits," adds Kuhr. "However, we needed to show that we really are able to manipulate each individual atom in the structure. This is crucial for encoding and reading out qubits and we are now at the beginning of setting up the first experiments of this kind."

There is also an article in Nature here.

Wired Magazine- Tech that never took: quantum computing

There's a recent story on Wired titled Tech That Never Took, within it is a short section on quantum computing (third one down here) by Tomas Hayden. It falls under the "tech that never took" category because the idea was introduced nearly three decades ago and our physical implementations are currently only a few handful of qubits at best. In the article Aaronson points out that the hard part of making a quantum computer is decoherence. When building a quantum computer you can think of this problem as basically being an unintended interaction with the environment which results in the state of the quantum computer not being maintained.

It is true that we've been working on it for a long time, but I disagree that quantum computing falls under the category of "tech that never took". It is taking us a long time because it is a really hard problem. Take another hard problem, developing the atomic bomb for example. It took a long time to create one, and we only did so when we did because of the huge amount of resources poured into the Manhattan Project. Another example is classical computers: much more than 3 decades elapsed between Charles Babbage's Difference Engine and the first real computers in the mid-twentieth century. My point is that just because it takes a long time to tackle a problem doesn't mean it will "never [take]".

Additionally we continue to make progress towards quantum computers, as I've outlined multiple times. My area is quantum software, not constructing the hardware, but I'd guess we're around a decade out from our first practical quantum computers. I'd also disagree with several of the other subjects listed in the article: nanotechnology, fusion power, personalized medicine, and self driving cars to name the most glaring ones to me. Given time, we've tackled some amazing problems, I don't see why these and quantum computing will be any different. Before 1903 there wasn't even powered flight by man, by 1969 we were landing people on the Moon.

7.5 Million in QC Funding

Levy out of the University of Pittsburg received 7.5 million (in US dollars) funding from the US Department of Defense to lead a team "...to tackle some of the most significant challenges preventing the development of quantum computers...". Full article here.

The Quantum Soul?

There's an article published yesterday on SFGate by Chopra and Hameroff titled Can science explain the soul? As the title implies it is pretty philosophical, but a large part of the discussion involves quantum mechanics and how they could tie in. Various interpretations and speculations on how quantum processes may have a deeper meaning are always interesting- this one is worth the quick read.

Free text: An Introductory Course on Quantum Mechanics

This was just posted on arXiv the other day: An Introductory Course on Quantum Mechanics by Bram Gaasbeek. The abstract:

This is a very gentle introductory course on quantum mechanics aimed at the first years of the undergraduate level. The basic concepts are introduced, with many applications and illustrations. Contains 12 short chapters of equal length, ideal for a one term course. The license allows reuse of figures and text under the Attribution-Noncommercial-ShareAlike conditions.

I skimmed through the table of contents and some of the text: some of the early chapters definitely seems applicable to some one new to quantum computing. I know I ended up spending quite a bit of money on books when I first started researching the subject, so one posted on arXiv is certainly a plus.

arXiv: Hiding Quantum Information in the Perfect Code

Here's another recent one from arXiv: Hiding Quantum Information in the Perfect Code by Shaw and Brun out of the University of Southern California. The abstract:

We present and analyze a protocol for quantum steganography where the sender (Alice) encodes her steganographic information into the error syndromes of the perfect (five-qubit) quantum error-correcting code, and sends it to the receiver (Bob) over a depolarizing channel. Alice and Bob share a classical secret key, and hide quantum information in such a way that to an eavesdropper (Eve) without access to the secret key, the quantum message looks like an innocent codeword with a typical sequence of quantum errors. We calculate the average rate of key consumption, and show how the protocol improves in performance as information is spread over multiple codeword blocks. Alice and Bob utilize different encodings to optimize the average number of steganographic bits that they can send to each other while matching the error statistics of the depolarizing channel.

As the paper says, there hasn't been much work in quantum steganography. It isn't my research area, but I think this is one of the few pieces on the subject that I've come across.

arXiv: Simulating Chemistry with Quantum Computers

I came across this in today's arXiv listing: Simulating Chemistry with Quantum Computers. Here's the abstract:

The difficulty of simulating quantum systems, well-known to quantum chemists, prompted the idea of quantum computation. One can avoid the steep scaling associated with the exact simulation of increasingly large quantum systems on conventional computers, by mapping the quantum system to another, more controllable one. In this review, we discuss to what extent the ideas in quantum computation, now a well-established field, have been applied to chemical problems. We describe algorithms that achieve significant advantages for the electronic-structure problem, the simulation of chemical dynamics, protein folding, and other tasks. Although theory is still ahead of experiment, we outline recent advances that have led to the first chemical calculations on small quantum information processors.

It is well known that a simulation of a general quantum system on a classical computer experiences an exponential slow down. As the title states, this paper describes how a quantum computer can be used to avoid this problem in Chemistry.