US Army and NSA Supporting Quantum Computing

Not too surprisingly, the US Army and NSA are looking for quantum computing proposals. There are 3 areas they're looking for, and they focus on physical implementations. Unfortunately quantum software isn't covered. As we've seen with classical computers, the physical implementation isn't much use without well written software.

Another Physical Advancement by NIST

NIST has created a quantum dimmer switch, another step forward towards physical implementations of quantum computers. (NIST announcement)

NIST Creates a 2 Qubit Programmable Quantum Computer

At the National Institute of Standards and Technology (NIST) they've done it again: they've created a 2 qubit programmable quantum computer. The key word here is programmable, it can carry out an arbitrary sequence of operations. We still need to scale things up, but this is another important milestone.

(NIST Post doc David Hanneke doing a demo of the quantum computer. Image from NIST.)

A Step Towards Practical Quantum Computers

This was passed on to me from the head of my Doctoral committee, Dr. Sanden: At NIST they've implemented successive quantum operations on qubits, in addition to multiple teleports. You can check out the article on Technology Review here.

While I'm not a physicist, and thus less involved in physical implementations of quantum computers, this is pretty exciting news. Decoherence is a big problem in physical implementations- essentially the state unintentionally collapsing through inadvertant measurement. When any measurement (perhaps partial) occurs the qubits collapse from possible superposition to a state that can be represented classically, that is by bits instead of qubits. So essentially one can think of decoherence as unintended measurements taking a system out of superposition.

(On a somewhat related note, this is why quantum operations must be reversible. Irreversible operations require energy to erase information, and input of energy acts as a measurement.)