Statistically induced phase transitions and anyons in 1D optical lattices

Tassilo Keilmann, Simon Lanzmich, Ian McCulloch & Marco Roncaglia

Nature Communications 2, 361 (2011) | doi:10.1038/ncomms1353

Press coverage:

• News Story: 'Anyons' Could Blur the Boson-Fermion Gap
  Discovery News Channel, November 2011
  
  
• News Story: Anyons, anyone?
  Symmetry Breaking (Fermilab), August 2011
  
  
• News Story: Wie sich Anyonen nachweisen ließen
  Der Standard (Austrian Newspaper), June 2011
  
  
• Blog Article: Acrobatics for anyons: New test for elusive fundamental particle proposed
  Physorg, June 2011
  
  
• Blog Article: Anyons: still hypothetical particles?
  Science Daily, June 2011

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  Anyons — particles carrying fractional statistics that interpolate between bosons and fermions — have been conjectured to exist in low-dimensional systems. In the context of the fractional quantum Hall effect, quasi-particles made of electrons take the role of anyons whose statistical exchange phase is fixed by the filling factor. Here we propose an experimental setup to create anyons in one-dimensional lattices with fully tuneable exchange statistics. In our setup, anyons are created by bosons with occupation-dependent hopping amplitudes, which can be realized by assisted Raman tunnelling. The statistical angle can thus be controlled in situ by modifying the relative phase of external driving fields. This opens the fascinating possibility of smoothly transmuting bosons via anyons into fermions and of inducing a phase transition by the mere control of the particle statistics as a free parameter. In particular, we demonstrate how to induce a quantum phase transition from a superfluid into an exotic Mott-like state where the particle distribution exhibits plateaus at fractional densities.