• Cold Baryogenesis from first principles in the two-Higgs doublet model with fermions 

      Mou, Zong-Gang; Saffin, Paul M.; Tranberg, Anders (Journal article; Peer reviewed, 2015-06)
      We present a first-principles numerical computation of the baryon asymmetry in electroweak-scale baryogenesis. For the scenario of Cold Baryogenesis, we consider a one fermion-family reduced CP-violating two Higgs-doublet ...
    • Optimisation of Thimble simulations and quantum dynamics of multiple fields in real time 

      Woodward, Simon; Saffin, Paul M.; Mou, Zonggang; Tranberg, Anders (Peer reviewed; Journal article, 2022)
      We apply the Generalised Thimble approach to the computation of exact path integrals and correlators in real-time quantum field theory. We first investigate the details of the numerical implementation and ways of optimizing ...
    • Quantum tunnelling, real-time dynamics and Picard-Lefschetz thimbles 

      Mou, Zonggang; Saffin, Paul M.; Tranberg, Anders (Peer reviewed; Journal article, 2019-11)
      We follow up the work, where in light of the Picard-Lefschetz thimble approach, we split up the real-time path integral into two parts: the initial density matrix part which can be represented via an ensemble of initial ...
    • Real-time quantum dynamics, path integrals and the method of thimbles 

      Mou, Zonggang; Saffin, Paul M.; Tranberg, Anders; Woodward, Simon (Peer reviewed; Journal article, 2019)
      Direct numerical evaluation of the real-time path integral has a well-known sign problem that makes convergence exponentially slow. One promising remedy is to use Picard-Lefschetz theory to flow the domain of the field ...
    • Simulations of "tunnelling of the 3rd kind" 

      Mou, Zonggang; Saffin, Paul M.; Tognarelli, Paul; Tranberg, Anders (Journal article; Peer reviewed, 2017-07)
      We consider the phenomenon of “tunnelling of the 3rd kind” [1], whereby a magnetic field may traverse a classically impenetrable barrier by pair creation of unimpeded quantum fermions. These propagate through the barrier ...
    • Simulations of a bubble wall interacting with an electroweak plasma 

      Mou, Zong-Gang; Saffin, Paul M.; Tranberg, Anders (Peer reviewed; Journal article, 2021-02)
      We perform large-scale real-time simulations of a bubble wall sweeping through an out-of-equilibrium plasma. The scenario we have in mind is the electroweak phase transition, which may be first order in extensions of the ...
    • Simulations of Cold Electroweak Baryogenesis: finding the optimal quench time 

      Mou, Zonggang; Saffin, Paul M.; Tranberg, Anders (Journal article; Peer reviewed, 2017-07)
      We revisit the numerical computation of the baryon asymmetry from Cold Electroweak Baryogenesis given the physical Higgs mass. We investigate the dependence of the asymmetry on the speed at which electroweak symmetry ...
    • Simulations of Cold Electroweak Baryogenesis: hypercharge U(1) and the creation of helical magnetic fields 

      Mou, Zonggang; Saffin, Paul M.; Tranberg, Anders (Journal article; Peer reviewed, 2017-06)
      We perform numerical simulations of Cold Electroweak Baryogenesis, including for the first time in the Bosonic sector the full electroweak gauge group SU(2) × U(1) and CP-violation. We find that the maximum generated baryon ...
    • Statistics on Lefschetz thimbles: Bell/Leggett-Garg inequalities and the classical-statistical approximation 

      Tranberg, Anders; Millington, P; Mou, Zonggang; Saffin, Paul M. (Peer reviewed; Journal article, 2021)
      Inspired by Lefschetz thimble theory, we treat Quantum Field Theory as a statistical theory with a complex Probability Distribution Function (PDF). Such complex-valued PDFs permit the violation of Bell-type inequalities, ...