## Imperial College London quantum computing

## Quantum Computers

A quantum computer represents, possibly, the ultimate form of quantum technology. The idea was born from various reasonings. The operation of a quantum computer is totally different from that of a conventional computer. While in the latter, information is represented by a definite number encoded on a string of 1s and 0s, a quantum computer allows the information to exist in a superposition of more than one state. This massive parallelism is one of the keys to the quantum speedup. However, there is an important rule in quantum mechanics which seems to deny this advantage – only one outcome can be obtained after the whole process. Thus, in order to utilise the massive parallelism provided by the quantum computer, algorithm should be developed carefully, taking the reality of the measurements in mind.

We provide PhD projects in relation to the hardware development of basic units of a quantum computer based on ions, atoms, photons and molecules. Our projects also include quantum simulations.

### Imperial College London quantum computing

## Quantum Information

This is an optional course taken from the final year Physics Undergraduate course. A summary is given in the current MSc Handbook. Other documents for this course (example sheets etc) are stored on Blackboard. The list below is indicative of the type of material covered in this course (taken from the 2015-16 course).

**Mathematical foundations of QI**

No cloning theorem, pure states, mixed states etc, generalized measurements, general evolution under completely positive maps.

**Quantum communication**

Teleportation/dense coding, Bell inequalities, generic properties of two-party pure state entanglement, entanglement as a powerful and interesting resource, elements of classical information theory, von Neumann entropy, Schumacher coding, information transmission channels

**Entanglement Theory**

Basic properties of entanglement: characterization/verification, manipulation (mixed state entanglement, distillation) and quantification

**Quantum computer science**

Notions of computational efficiency, classical and quantum gates and circuits, Examples of quantum gate implementations in ion traps, cavity QED, photons. Quantum algorithms: Deutsch/Jozsa algorithm, Grover’s algorithm