Available student project - Quantum coherence and metrology

Research fields

  • Theoretical Physics
  • Quantum Science and Applications
(a) Input states that are fully incoherent (S and A) cannot be converted to entanglement via incoherent operations. (b) But when the input state S has coherence, the coherence can be converted to entanglement. Credit: Streltsov, et al.

Project details

In order to be able to do science, we need a way to quantify things. For example, finding a way to quantify "temperature" and "heat" led to the development of thermodynamics.

But how do we quantify "quantumness"? A popular way to measure quantumness is by measuring entanglement. We can say that a bi-partite system is more quantum if it is more entangled. This is justifiable since entanglement can be used as a resource to perform tasks such as dense-coding and device-independent quantum key distribution which would otherwise not be possible.

Lately, several new measures of quantumness have been proposed. They include: discord, negativity of wigner-function, interferometric power and coherence to list a few. A state has "coherence" if it is in a superposition of some classical states. Each of these measures measures a different aspect of quantumness. But they can be interrelated. For example, coherence can be converted to entanglement via incoherent operations.

The aim of this project is to find a relation between some of these measures. We also aim to explore new distance based measures of quantumness and investigate their properties. Specifically, we aim to establish a link between coherence and quantum metrology. A state with high coherence will provide better precision when used for metrology.

Project suitability

This research project can be tailored to suit students of the following type(s)
  • 3rd year special project
  • PhB (2nd or 3rd year)
  • Honours project
  • Phd or Masters
  • Vacation scholar

Contact supervisor

Assad, Syed profile
Research Associate
(02) 612 57994

Other supervisor(s)

Lam, Ping Koy profile
CQC2T Node Director
(02) 612 58378

Updated:  15 January 2019/ Responsible Officer:  Director, RSPE/ Page Contact:  Physics Webmaster