- Hugo Creeth

# The Quantum Conundrum

The field of quantum computing was initiated by the work of Paul Benioff and Yuri Manin in 1980, then again by Richard Feynman in 1982 and subsequently David Deutsch in 1985.

# What is Quantum Computing?

Put simply (or not) it is computing using quantum-mechanical phenomena, such as superposition and entanglement.

**1. Superposition** - A fundamental principle of quantum mechanics. It states that any two (or more) quantum states can be added together ("superposed") and the result will be another valid quantum state.

This state has previously been explained using Schrödinger's Cat devised by Austrian physicist Erwin Schrödinger in 1935. The scenario presents a cat that may be simultaneously both alive and dead - Superposition.

During the description of the paradox Erwin used the phrase "Verschränkung" which has since become - Entanglement.

**2. Entanglment** - As the name suggest is a physical phenomenon which occurs when pairs or groups of particles are generated or interact in ways such that the quantum state of each particle cannot be described independently of the state of the other, therefore they are "Entangled".

# What is a Quantum Computer?

A quantum computer is a device that performs quantum computing by utilising both Superposition and Entanglment.

A quantum computer is different from ordinary everyday binary computers which are based on transistors. These common digital computers require data to be encoded into binary digits (bits), each of which is always in one of two definite states (0 or 1) - Yes OR No.

Quantum computation uses quantum bits (Qubits), which can be in superpositions of states. That means that they can be both Yes AND No simultaneously!

This means they are faster and far superior in computing power to traditional computers.

In order to make these Qubits powerful and fundamentally useful then they need to be joined or entangled together. Each time a Qubit is added together then the harnessing power is doubled.

## Qubits x 2 = Computational Power

# Why is it so difficult?

The fundamental issue with this idea is that Qubits are incredibly unstable. They get even more unstable the more they are entangled. The instability means that any external forces can cause huge errors in computing and ultimately lead to them breaking down.

Therefore huge efforts are being made in scientific research to find ways to generate Qubit processors which are stable.

## Breakthrough

A recent paper published in Nature has offered a new and exciting piece to the puzzle that will hopefully make quantum computing more commonplace in the future.

The paper explained how a team from Delft University developed a programmable quantum processor made with silicon.

The team used microwave energy to align two electron particles suspended in silicon, then used them to perform a set of test calculations.

By using silicon, the scientists hope that quantum computers will be more easy to control and manufacture.

An exciting step forward but the quantum conundrum still remains...