Alexander, Tristram JSukhorukov, AndreyKivshar, Yuri2009-08-252010-12-202009-08-252010-12-20Physical Review Letters 93.6 (2004): 063901/1-40031-90071079-7114http://hdl.handle.net/10440/766http://digitalcollections.anu.edu.au/handle/10440/766We reveal the existence of asymmetric vortex solitons in ideally symmetric periodic lattices and show how such nonlinear localized structures describing elementary circular flows can be analyzed systematically using the energy-balance relations. We present the examples of rhomboid, rectangular, and triangular vortex solitons on a square lattice and also describe novel coherent states where the populations of clockwise and anticlockwise vortex modes change periodically due to a nonlinearityinduced momentum exchange through the lattice. Asymmetric vortex solitons are expected to exist in different nonlinear lattice systems, including optically induced photonic lattices, nonlinear photonic crystals, and Bose-Einstein condensates in optical lattices.4 pageshttp://www.sherpa.ac.uk/romeo/index.php "Author can archive pre-print (ie pre-refereeing) … post-print (ie final draft post-refereeing) … [and] publisher's version/PDF. Link to publisher version … [and] Copyright notice required. Publisher's version/PDF can be used on … employers web site." - from SHERPA/RoMEO site (as at 25/02/10). ©2004 The American Physical SocietyKeywords: Energy density; Periodic lattices; Photonic lattices; Waveguide arrays; Crystal lattices; Crystal symmetry; Hamiltonians; Light propagation; Light reflection; Mathematical models; Photons; Solitons; Spectrum analysis; Vortex flow; Nonlinear opticsAsymmetric vortex solitons in nonlinear periodic lattices2004-08-0310.1103/PhysRevLett.93.0639012016-02-24