Photonic Quantum Computing may be Closer Than Previously Thought

Physicists are investigating the possibility of using photons of light to develop large-scale quantum computing, or in other words, photonic quantum computing.

Scientists and engineers working on quantum computers follow the same physical principles, but not the same paths.

Among the most researched approaches to quantum computing, we find the architecture based on trapped ions and superconductors.

Trapped ions quantum computers are the furthest ahead in the game as they’re already available in the market for corporate clients (D-Wave computers). However, they don’t lend themselves very well to scaling up.

For any of the proposed methods for large-scale quantum computing to work, there are two crucial requirements.

First, the system has to maintain qubits in a stable and completely isolated environment that ensures the integrity of information without the need for extremely low temperatures.

Two, the system must be made up of controllable qubits via entangling transistors.

Qubits can be any kind of atomic particles that allow such features. In this regard, photons may be the best option.

Silicon Photonics, or Photonic Quantum Computing

Another technological path that seems to be particularly promising is photonic quantum computing.

Quantas of light, or photons, are literally lightning fast, massless, and incredibly stable which make them attractive targets as qubits.

Some researchers believe two-dimensional chips packed with entangled photons are the most likely to take quantum computing to the next stage.

Terry Rudolph, Professor at the Department of Physics of Imperial College London thinks that silicon-photonics will be the swan-to-be of quantum computers.

Rudolph lists two reasons as to why we should pursue photonic integrated circuits (PICs).

With PICs, engineers can “reduce stochastic noise levels several orders of magnitude below even optimistic estimates of such noise for matter-based approaches… The second reason is that PICs are being vigorously pursued for classical computing purposes, and the core components necessary for the quantum architecture are already under investigation and optimization,” said Rudolph.

What’s more, using photons as carriers of information between the various components of quantum computing systems have three major advantages:

Lightspeed information processing and transfer.
Energy efficiency.
Easy integrability into current silicon chip industry.

Photonic scientists and engineers are making the necessary steps to accelerate the industrialization of photonic quantum computing.

Blind (Photonic) Quantum Computing

Among the research groups working on photonic quantum computing is the Quantum Information Science and Quantum Computation Group at the University of Vienna, Austria.

The QISQC group is mainly focussed on Blind Quantum Computing (BQC).

The concept of blind quantum computing is interesting because it allows clients to delegate tasks to quantum servers that they don’t possess.

The word “blind” here is all about the security of outsourced material as quantum servers carry out tasks given to them without having full access to information that might be compromising.

What the QISQC physicists brought to the BQC table is that their platform doesn’t require clients to own big quantum capabilities to be able to outsource tasks.

About their BQC protocol, researchers said it “allows a client with limited quantum capabilities to delegate a computation to a quantum server without leaking input, output or the algorithm of the computations.”