Title: Quantum Correlations in Space & Time
Speaker: Joe Fitzsimons (Singapore University of Technology and Design)
Abstract: In ordinary, non-relativistic, quantum physics, time enters only as a parameter and not as an observable: a state of a physical system is specified at a given time and then evolved according to the prescribed dynamics. While the state can, and usually does, extend across all space, it is only defined at one instant of time, in conflict with special relativity where space and time are treated on an equal footing. In this talk, I will examine the consequences of extending the notion of the quantum density matrix to multiple spatial and temporal measurements. To this end, I will introduce the concept of a pseudo-density matrix which treats space and time indiscriminately. This matrix in general fails to be positive for timelike separated measurements, motivating the definition of a measure of causality that discriminates between spacelike and timelike correlations. I will present the results of recent NMR experiments to measure causal correlations and their decay under the effects of noise. In the second half of the talk, I will present an application on the pseudo-density framework to bounding the capacity of quantum channels, and show how it can be used to obtain new bounds for the capacity of shifted depolarizing channels.
Time: Tuesday 6th March 2018, 2.30pm.
Place: Lecture Room, School of Theoretical Physics, DIAS, 10 Burlington Road, Dublin 4.
Leave a Comment
Last Updated: 23rd May 2018 by George Rogers
Tuesday 6th March: STP Seminar – “Quantum Correlations in Space & Time”
Title: Quantum Correlations in Space & Time
Speaker: Joe Fitzsimons (Singapore University of Technology and Design)
Abstract: In ordinary, non-relativistic, quantum physics, time enters only as a parameter and not as an observable: a state of a physical system is specified at a given time and then evolved according to the prescribed dynamics. While the state can, and usually does, extend across all space, it is only defined at one instant of time, in conflict with special relativity where space and time are treated on an equal footing. In this talk, I will examine the consequences of extending the notion of the quantum density matrix to multiple spatial and temporal measurements. To this end, I will introduce the concept of a pseudo-density matrix which treats space and time indiscriminately. This matrix in general fails to be positive for timelike separated measurements, motivating the definition of a measure of causality that discriminates between spacelike and timelike correlations. I will present the results of recent NMR experiments to measure causal correlations and their decay under the effects of noise. In the second half of the talk, I will present an application on the pseudo-density framework to bounding the capacity of quantum channels, and show how it can be used to obtain new bounds for the capacity of shifted depolarizing channels.
Time: Tuesday 6th March 2018, 2.30pm.
Place: Lecture Room, School of Theoretical Physics, DIAS, 10 Burlington Road, Dublin 4.
Category: News, Regular seminars, School of Theoretical Physics News & Events, Seminars
Here is when you will be able to see the 'Super Blood Wolf Moon' this weekend via @irishexaminer #DIASdiscovers irishexaminer.com/breakingnews/i…
Great to see our very own Dr Rebeca Garcia Lopez featured in both the @irishexaminer and the @Independent_ie as one of 20 @scienceirel Starting Investigator Research Grant awardees. #DIASdiscovers
Great piece by @KOSullivanIT in the @IrishTimes today on the unveiling of Shei;a Tinney's portrait yesterday at DIAS with @mitchelloconnor and the family of Dr Tinney. Read it online here: bit.ly/2FvErVs
We were delighted to have @mitchelloconnor , Minister of State for Higher Education, with us on this special occasion today. twitter.com/DIAS_Dublin/st…
We are so proud of Dr Rebeca Garcia Lopez who is one of 20 to receive funding under the @scienceirel SIRG programmes. Congratulations, Rebeca - it is so deserved! #DIASdiscovers twitter.com/scienceirel/st…
A proud day for DIAS, celebrating our past and present female scientists: news that Dr Rebeca Garcia Lopez (DIAS) has received funding via @scienceirel Starting Investigator Research Grant & unveiling of the portrait of renowned scientist & 1st female Fellow of DIAS,Sheila Tinney
Some final words from Sheila’s daughter, Deirdre. #DIASdiscovers
The beautiful portrait of Sheila Tinney, by Judith Henihan, officially unveiled by the family of Sheila and @mitchelloconnor
We’re now moving on to the official unveiling of the portrait by Minister Mary Mitchell O’Connor @mitchelloconnor #DIASdiscovers
Sheila Tinney’s daughter Ethna tells us how she recalls her mother remarking approvingly how De Valera initiated the establishment of DIAS #DIASdiscovers
We are delighted to be joined by the daughters and son of Sheila Tinney here at DIAS today for the unveiling. Her son Hugh speaking now on her extensive career as a scientist #DIASdiscovers
Today we’re hosting a very special lunchtime reception to unveil a portrait of former DIAS Fellow and renowned scientist, Sheila Tinney #DIASdiscovers
We were sad to hear of the passing of Sir Michael Atiyah last week, aged 89. Atiyah was a great former chair of the board of our School of Theoretical Physics here at DIAS from 2000-2005. Ar dheis Dé go raibh a anam dílis. (Below, pictured in DIAS's Conference Room) @StpDias
Congrats to @StKiliansDS team Roan Batard, Ethan McQuaid & Marilou Gerbelot-Barillon on winning the Group 2nd place in Physical, Chemical & Mathematical Sci at @BTYSTE lfor their project: 'What makes Dublin shake?' @dias_geophysics were delighted to support you with your project! twitter.com/NBourgeois_Pro…