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SUMMARY:On the creation and evolution of quantum knots and links - Renzo R
 icca\, U. Milano-Bicocca
DTSTART:20230317T160000Z
DTEND:20230317T170000Z
UID:TALK195043@talks.cam.ac.uk
CONTACT:Prof. Jerome Neufeld
DESCRIPTION:By exploiting the hydrodynamic formulation of the Gross-Pitaev
 skii equation (GPE) for quantum fluids we present new results on the creat
 ion and evolution of defects forming knots and links [1]. Direct and inver
 se topological cascades are discussed\, showing how a trefoil knot is crea
 ted by the interaction and reconnection of initially unknotted\, unlinked 
 loops. The zero helicity condition is proven by writhe and twist exchange\
 , and the analysis of kinetic and quantum energy contribution on phase sur
 faces shows that defect evolution is governed by minimal surface energy dy
 namics [1\,2]. Moreover\, considering a twist phase superposition on exist
 ing defects we prove that new phase defects can be produced as a manifesta
 tion of a Aharonov-Bohm type effect [3] by an instability criterium derive
 d from a modified form of the GPE [4].\n\n[1] Zuccher\, S. & Ricca\, R.L. 
 (2022) Creation of quantum knots and links driven by minimal surfaces. J. 
 Fluid Mech. 942\, A8.\n\n[2] Sumners\, De W.L.\, Cruz-White\, I.I. & Ricca
 \, R.L. (2021) Zero helicity of Seifert framed defects. J. Phys. A: Math. 
 Theor. 54\, 295203.\n\n[3] Foresti\, M. & Ricca\, R.L. (2019) Defect produ
 ction by pure phase twist injection as Aharonov-Bohm effect. Phys. Rev. E 
 100\, 023107.\n\n[4] Foresti\, M. & Ricca\, R.L.. (2022) Instability of a 
 quantum vortex by twist perturbation. J. Fluid Mech. 949\, A19.
LOCATION:MR2\, Centre for Mathematical Sciences\, Wilberforce Road\, Cambr
 idge
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