Paper detail

A Protocol for Spectroscopists to Isolate The Effect of Berry Geometric Magnetic Forces on Molecular Dynamics

We propose a novel means to isolate and quantify the effects of Berry force on molecular dynamics using two reasonably strong continuous wave (CW) laser fields with frequencies $ω$ and $2ω$. For molecules or materials with three frequency-matching bright transitions ($|{0}\rangle\rightarrow|{1}\rangle$, $|{1}\rangle\rightarrow|{2}\rangle$, $|{0}\rangle\rightarrow|{2}\rangle$) at frequencies ($ω$, $ω$, $2ω$) respectively, the effects of Berry curvature can be isolated by varying the phase between the two laser fields ($Δϕ$) and monitoring the dynamics. Moreover, we find that the resulting chemical dynamics can depend critically on the sign of $Δϕ$; in other words, the effects of Berry curvature can be enormous. Thus, this manuscript represents an unusual step forward towards using light-matter interactions to affect chemical dynamics, suggesting that topological concepts usually invoked in adiabatic quantum optics and condensed matter can be directly applied to non-adiabatic chemical excited state dynamics.