The processor is at the heart of a computer. It receives inputs, performs manipulations on the inputs and then provides outputs. Unlike conventional computing bits, which can be in one of only two states at any one time (either 1 or 0), a qubit - a quantum bit - can be in multiple states at the same time. Therefore qubits can be used to hold and process a much larger amount of information at a greater speed. This quantum phenomenon is known as superposition.
Photons can also interfere with each other and share their quantum state. This quantum phenomenon is known as entanglement and was described by Albert Einstein as “a spooky action at a distance”. The interaction continues even when the particles are no longer near each other and is hard to understand in terms of our everyday world. An action on one entangled quantum particle will result in an instantaneous action on the other entangled particle conserving the laws of energy and momentum. But, you cannot guarantee which way you will influence them so we rely on statistical probabilities to tell us what the most likely result of an action is.
The quantum processor in our lab will allow you to create and manipulate your own qubits and measure the quantum phenomena of superposition and entanglement. The processor works by repeatedly sending the prepared photons through the circuit and measuring where the photons emerge. Over many iterations this data builds up a statistical picture over that tells you what is happening to the photons.
Our processor allows for the input of 2 photons prepared as qubits. The qubits can be manipulated using phase shifters - little heaters which change the speed of the photons through the waveguide. By changing the relative phases of the photons it is possible to change the state of the qubit.
Before using our processor we recommend you first try out the simulator as this will help you decide the settings for the processor – once you have input your settings they can’t be changed until the experiment has run, which may take a few minutes.