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Work on Dynamic shear suppression in quantum phase space finally explains the emergence of Zurek’s scale in phase space. This is due to a kind of ‘stickiness of quantum dynamics in phase space’. This leads to a suppression of the shear of distributions in phase space observed in classical systems such as chaotic systems.

Our work does not only identify the mechanism by which quantum dynamics suppresses classical dynamical shear, it additionally quantifies this behaviour leading to a new theoretical measure to probe the dynamics of quantum systems. Applying our measure we find that it sensitively and robustly picks out the most surprising states the quantum evolution creates.

We hope this will be useful to the community as a new measure to monitor what a quantum system is doing.
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Work on Anharmonic quantum mechanical systems do not feature phase space trajectories shows that the formation of quantum coherences (negativities of Wigner distribution) cannot be viewed from a perspective of classical phase space transport. If one does adopts a classical approach and tries to understand quantum phase space evolution from a perspective of classical transport along trajectories paradoxes arise: Liouvillian phase space volumes shrink or expand infinitely quickly, trajectories do not exist globally, computer code breaks down.
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Work on Structures far below sub-Planck scale in quantum phase-space through superoscillations shows that the Wigner distribution can show structure on scales much finer that Zurek’s phase space interference argument stipulates. We showed this by mapping superoscillating functions into phase space.
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Work on Wigner’s representation of quantum mechanics in integral form and its applications shows that Wigner current J can be expressed in integral form. This makes certain symmetries more transparent and also allowed us to give a simple proof that J’s non-vanishing divergence cannot be transformed away (resolving a previously open question).
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The paper equivalence of harmonic oscillators with free particles in quantum mechanics pulls together several previously published ideas and some new material to show how the equivalence can be used to model the trapping and release of quantum particle.
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Work on Wigner current J, in collaboration with Dimitris Kakofengitis and Georg Ritter, establishes the quantum analog of classical particle flow along phase portrait lines.
This is surprising because Heisenberg’s uncertainty principle seems to preclude the existence of phase portraits.

Our work reveals hidden features of quantum dynamics and extra complexity. Being constrained by conserved flow winding numbers, it also introduces topological order into quantum dynamics. For details see the press release, the manuscript or the journal cover.

If you are interested in further details still, see these animations [8Mb] and a youtube video that illustrates topological charge conservation in the system we studied.
Here is a link detailing some of the Media Echo.
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In work from 2012 I investigate helices of light. Intensity helices of light that is. They can arise as an interference phenomenon. It turns out that threads of darkness, dark helices, fare better than bright ones. They are less constrained by optical resolution limits.
Dark helices are much more sharply defined than bright helices when you ”see” them on a logarithmic scale, photo-resists tend to do just that. They are potentially more useful in laser tweezing arrangements since they are dark. This means less light is scattered when you trap a low field seeking particle. That may turn out be important for applications such as atom-trapping, trapping of molecules with handedness in solution, or bulk production of helical photo-lithographic imprints; to create metamaterials, say.
For details see the article at Optics Express http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-20-13-14371.
Here is a link detailing some of the Media Echo.
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There has been some media interest in Daniel Polani’s and my 2010-work on ”How to kill persistent bugs”: (10.1109/TEVC.2010.2040181 arXiv:q-bio/0512003v2).
Here is a link detailing some of the Media Echo.
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PIC

Dr Ole Steuernagel
University of Hertfordshire
Hatfield, Herts AL10 9AB, UK
T: +44 (0) 1707 284600
E: O.Steuernagel @ herts.ac.uk

Last updated: December 10, 2018

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