Quantum technology is a key technology that enables new products and services. The potential of quantum computers, simulators, networks, and sensors holds enormous promise for society, industry, and science. This brings us to the brink of a technological revolution that can help provide solutions to a variety of major societal challenges.

Quantum mechanics is about particles smaller than atoms. These particles have special properties that are used in quantum technology for technological innovations, from extremely fast computers to long-distance data communication.

Two key principles for understanding quantum technology come from quantum mechanics. These principles involve small particles that exhibit unusual behaviour, which we call superposition and entanglement.

**Superposition**

A quantum particle can be in several states at once; it can be in several places at once, for example. This is called superposition. Only when we take a measurement do we record the position. So, this is different from, for example, a coin, where we know that either heads or tails is facing upward, but not a combination of the two which is only determined when we look at the coin.

**Entanglement**

Two or more quantum particles, such as photons or electrons, can combine to form a single system. These particles appear connected by an invisible bond, which is known as entanglement. If two particles are entangled, by measuring the state of one particle, you immediately know more about the state of the other particle, even if they are at a great distance from each other. They seem to communicate and exchange information faster than the speed of light.

The unusual behaviour of small quantum particles allows the technology to be used for a variety of applications. Below we explain four applications that the WACQT research programme is working on, and which WACQT-IP AB is trying to find commercial potential for:

**1. Quantum computer: solving complex calculations**

A quantum computer calculates differently than a classical computer. The classical computer calculates using bits, which are units of digital information that have a value of 0 or 1. In a quantum computer, the quantum bits, also known as qubits, can be 0 and 1 at the same time. This allows qubits to collectively be in a superposition of all possible states.

Qubits give quantum computers tremendous processing speed. This is because they do not go through all the options one by one but can test them all at the same time. Quantum computers can solve complex problems that are virtually unsolvable for classical computers because the calculation would take centuries.

Creating a quantum computer is complex. Presently, there is quantum computer at Chalmers for research purposes, and a copy of this will be built to be open for industry to test simulations etc.

**2. Quantum simulation: simulating complex systems**

A quantum simulator is a quantum computer with one specific application (‘special purpose quantum computer’). These simulators make it possible to solve solid-state physics, quantum chemistry, materials science, and high-energy physics problems. Through the quantum mechanical interactions between atoms, electrons, and photons, a quantum simulator can mimic other complex systems.

**3. Quantum communication: secure data connections**

Entanglement plays an important role in quantum communication. Entanglement of qubits allows the state of entangled particles to match, even over long distances. What's more, qubits can’t be copied with preservation of superposition. Any attempt to intercept qubits is, therefore, detected. That's why quantum communication is potentially extremely secure.

In the WACQT programme they model, simulate, and integrate quantum networks, and explore the various application possibilities of quantum communication.

**4. Quantum sensing: high-quality measurement**

Quantum sensors can detect changes in temperature, radiation, acceleration, time, and electric or magnetic fields. This is because they are more sensitive and have a higher resolution than classical sensors. This enables, for example, the measurement of extremely small structures, such as DNA. The first systems with quantum sensors are now available. And in the longer term, this will lead to better navigation systems, radar systems, and medical detection techniques.