EPSRC Reference: 
EP/L001578/1 
Title: 
Quantum Critical Dynamics of Tensor Networks 
Principal Investigator: 
Green, Professor AG 
Other Investigators: 

Researcher CoInvestigators: 

Project Partners: 

Department: 
London Centre for Nanotechnology 
Organisation: 
UCL 
Scheme: 
Standard Research 
Starts: 
01 July 2013 
Ends: 
30 June 2015 
Value (£): 
207,987

EPSRC Research Topic Classifications: 

EPSRC Industrial Sector Classifications: 
No relevance to Underpinning Sectors 


Related Grants: 

Panel History: 
Panel Date  Panel Name  Outcome 
22 May 2013

Developing Leaders Meeting  LF

Announced


Summary on Grant Application Form 
One of the strangest aspects of quantum mechanics is the idea of action at a distance, whereby if two particles are prepared in a certain state relative to one another and then separated to opposite sides of the galaxy, a measurement on one of them will instantaneously tell one about the state of the other. This so worried Einstein that it gave him a deep suspicion about the theory of quantum mechanics. Nevertheless, experiment after experiment has confirmed that that is just how the universe is. If an intuitive understanding of this escapes us, we at least now know how to quantify the amount of this "quantumness" in a measure called entanglement.
The situation is even trickier when we think about systems with many particles. In this case we can imagine that every pair of particles might be entangled with one another. An important insight about the real world, however, is that for a variety of reasons usually pairs of particles are not entangled with one another if they are more than a certain distance apart. A certain type of wavefunction can be written down that encodes this idea of a finite range of entanglement mathematically. These states are known as tensor network states.
The use of these states is relatively new, but already their impact is profound and farreaching. They have enabled the behaviour of manyparticle quantum systems to be simulated on a computer with unprecedented accuracy. At the same time, insights flowing from the way in which these states behave has enabled us to make some hitherto unsuspected connections between quantum systems  including ultimately a link between the theory of black holes and the quantum mechanics of electrons in certain types of crystals known a quantum critical.
In this project we will use tensor network states to try to understand the dynamics of quantum critical systems  systems that in a certain sense are balanced between being classical and quantum mechanical. Our hope is that in doing so, we will find new ways of modelling quantum systems efficiently on computers, new ways of thinking about the quantum world and new ways to harness it to technological ends.

Key Findings 
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Impacts 
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Summary 

Date Materialised 


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