What are quantum technologies?
Quantum technologies (QT) is a new field in physics and engineering. It relies on the unusual properties of quantum systems, as for instance, their ability to be in different states at the same time, a property called superposition. They can also be deeply connected without any direct physical interaction, a situation described as entanglement.
There exist currently many devices which are fundamentally reliant on the effects of quantum mechanics. These include for instance laser systems, transistors and semi-conductor devices and MRI imagers. Such devices are often referred to belonging to the first quantum revolution. Quantum technologies are often described as the second quantum revolution or 'quantum 2.0'. These are generally regarded as a class of device that actively create, manipulate and read out quantum states of matter, often using the quantum effects of superposition and entanglement.
QT are expected to lead to many fundamentally new applications:
Sensing: Quantum superposition states can be very sensitive to a number of external effects such as electric, magnetic and gravitational fields and therefore can be used to make very sensitive sensors for high-precision measurements.
Computing: quantum computers are devices that can store and process quantum data, or qubits. In doing this, quantum computers are predicted to calculate certain algorithms significantly faster than even the largest classical computer available today.
Secure communications: Quantum secure communications are expected to be safe in the advent of quantum computing systems that could break current cryptography systems. One significant component of quantum secure communication systems is expected to be quantum key distribution, a method of transmitting information using entangled light in a way that makes any interception of the transmission obvious to the user.
Simulation: complex quantum systems are impossible to model with a supercomputer. In this instance, quantum simulators are special purpose devices designed to provide insight about specific physics problems.