Applications of Quantum

Entanglement

Team Fx

A. Ball

S.T.J. O’Neill

P.G. O’Shea

P.M. Plesniak

T.A.O. Rashid

Quantum Entanglement

• For two entangled particles, a change in one effects

the other regardless of the distance between

• Suggests faster than light travel – ‘Spooky action at a

distance’

• Can happen naturally or in labs

• Cannot measure the quantum state of two particles –

measuring one destroys the entangled state

• Has many applications in physics

Timekeeping

• Standard clocks depend on location

• Quantum clocks are absolute

• Current definition of a second hard to maintain

• May entangle single atoms which oscillate in specific

modes, emitting specific frequency of energy

• Multiple entangled atoms per clock

• Clocks distributed on satellites, creating a better UTC

Fig.1: Diagram showing

Research at Imperial

• 2013 research project by Prof. Ed Hinds in the

Centre for Cold Matter on ultra-precise clocks and

sensors

• Involved crating a portable device for creating ultra-

cold atoms

• This is key for development of quantum clocks

Quantum Computing

• Calculations currently use binary operations

• Recent use of particles’ quantum states, with

calculations performed using Principle of

Superposition

• E.g. Spin

• Information stored as qubits

• Calculations based on end product of interference

• Quantum computers should be more efficient by

2030

Fig.2: Google’s D-Wave quantum

computer. Recently doubled processing to

1000 qubits, and can do calculations

“Teleportation, or the ability to transport a person or

object instantly from one place to another, is a

technology that could change the course of civilisation

and alter the destiny of nations”. Physics of the Impossible, Michio Kaku

Quantum Teleportation

• Requires entangled pairs of particles

• To the observer a particle will simultaneously take

the others’ quantum state

• This is instantaneous

• It is termed ‘Quantum teleportation’

Fig.3: Diagram showing basic

principles of quantum teleportation

Experiments in Quantum Teleportation

1963 - IBM 2004 – University of Vienna

1997 – University of Innsbruck 2015 - NIST

The NIST Experiment

• Uses time-bin encoding, instead of polarisation of

photons, as the quantum information sent

• This is preserved better over large distances

• Encoded with Mach-Zender interferometer

Fig.4: Mach-Zender Interferometer

Experimental Results

• Four fold improvement over previous experiments

• Successful over 80% of the time

• Similar results to those over much shorter distances

• Could lead to quantum networks

Quantum Cryptography

• Particle transferred via entanglement to receiver

• System cannot be measured without being disturbed

• Receiver immediately notified

• E.g. BBN Technologies and Toshiba

• Only used over 88 miles so far

Fig.5: Diagram showing the basic

principles of quantum cryptography