We present a theoretical study of atom - molecule collisions in superimposed electric and magnetic fields show that dynamics electronic spin relaxation molecules at temperatures below 0.5 K can be manipulated by varying the strength relative orientation applied fields. The mechanism field control Zeeman transitions is based on an intricate interplay between intramolecular spin-rotation couplings molecule-field interactions. suggest may affect chemical reactions through inducing nonadiabatic...

Cold molecules promise to reveal a rich set of novel collision dynamics in the low-energy regime. By combining for first time techniques Stark deceleration, magnetic trapping, and cryogenic buffer gas cooling, we present experimental observation cold collisions between two different species state-selected neutral polar molecules. This has enabled an absolute measurement total trap loss cross sections OH ND(3) at mean energy 3.6 cm(-1) (5 K). Due dipolar interaction, section increases upon...

We present an experimental and theoretical study of atom-molecule collisions in a mixture cold, trapped atomic nitrogen NH molecules at temperature $\sim 600$~mK. measure small N+NH trap loss rate coefficient $k^{(\mathrm{N+NH})}_\mathrm{loss} = 8(4) \times 10^{-13}$~cm$^{3}$s$^{-1}$. Accurate quantum scattering calculations based on {\it ab initio} interaction potentials are agreement with experiment indicate the magnetic dipole to be dominant mechanism. Our theory further indicates ratio...

We present a theoretical study of noise-induced quantum coherences in model three-level $V$-type system interacting with incoherent radiation, an important prototype for wide range physical systems ranging from trapped ions to biomolecules and dots. By solving the optical equations motion, we obtain analytic expressions show that they exhibit oscillating behavior limit large excited level spacing $\mathrm{\ensuremath{\Delta}}$...

We present an efficient theoretical method for calculating the time evolution of density matrix a multilevel quantum system weakly interacting with incoherent light. The combines Bloch-Redfield theory partial secular approximation one-photon coherences, resulting in master equation that explicitly exposes reliance on transition rates and angles between dipole moments energy basis. modified allows unambiguous distinction regimes coherent vs. transfer under light illumination. fully regime is...

We propose a general protocol for on-demand generation of robust entangled states nuclear and/or electron spins ultracold $^1\Sigma$ and $^2\Sigma$ polar molecules using electric dipolar interactions. By encoding spin-1/2 degree freedom in combined set spin rotational molecular levels, we theoretically demonstrate the emergence effective spin-spin interactions Ising XXZ forms, enabled by efficient magnetic control over show how to use these create long-lived cluster squeezed states.

Coherent control of atomic and molecular scattering relies on the preparation colliding particles in superpositions internal states, establishing interfering pathways that can be used to tune outcome a process. However, incoherent addition different partial wave contributions integral cross-sections, commonly encountered systems with complex collisional dynamics, poses significant challenge, often limiting control. This work demonstrates time-reversal symmetry overcome these limitations by...

Closed-form analytic solutions to non-secular Bloch-Redfield master equations for quantum dynamics of a V-type system driven by weak coupling thermal bath, relevant light harvesting processes, are obtained and discussed. We focus on noise-induced Fano coherences among the excited states induced incoherent driving V-system initially in ground state. For suddenly turned-on driving, time evolution is determined damping parameter ζ=12(γ1+γ2)/Δp, where γi radiative decay rates levels i = 1, 2,...

Open quantum systems interacting with a thermal environment are formally treated by secular or nonsecular master equations, the equation predicting distinct dynamics unobserved noise-induced Fano coherences. The authors propose an experimental test to examine master-equation applicability and existence of coherences in atomic system excited incoherent light.

We show that quantum interference-based coherent control is a highly efficient tool for tuning ultracold molecular collision dynamics free from the limitations of commonly used methods rely on external electromagnetic fields. By varying relative populations and phases initial superpositions degenerate states, we demonstrate complete over integral scattering cross sections in $s$-wave regime both final channels. The proposed methodology applied to ${\mathrm{O}}_{2}+{\mathrm{O}}_{2}$...

The authors present a detailed study of low-temperature collisions between CaD molecules and He atoms in superimposed electric magnetic fields with arbitrary orientations. Electric do not interact the electron spin directly but modify their rotational structure and, consequently, spin-rotation interactions. examine molecular Stark Zeeman energy levels as functions angle show that rotating may induce shift avoided crossings rotationally ground excited states molecule. dynamics are extremely...

We measure and theoretically determine the effect of molecular rotational splitting on Zeeman relaxation rates in collisions cold 3Sigma molecules with helium atoms a magnetic field. All four stable isotopomers imidogen (NH) molecule are magnetically trapped studied 3He 4He. The 4He data support predicted 1/B_{e};{2} dependence collision-induced rate coefficient constant B_{e}. measured coefficients much larger than coefficients, depend less strongly B_{e}, theoretical analysis indicates...

We present an accurate quantum mechanical study of molecule–molecule collisions in the presence a magnetic field. The work focuses on analysis elastic scattering and spin relaxation O2(3Σg–) molecules at cold (∼0.1 K) ultracold (∼10–6 temperatures. Our calculations show that is extremely efficient except fields below 1 mT. rate constant for T=0.1 K field 0.1 T found to be as large 6.1×10–11 cm–3 s–1. dependence inelastic cross sections temperatures dominated by manifold Feshbach resonances...

The prospects of sympathetic cooling polar molecules with magnetically cotrapped alkali-metal atoms are generally considered poor due to strongly anisotropic atom-molecule interactions leading large spin relaxation rates. Using rigorous quantum scattering calculations based on ab initio interaction potentials, we show that inelastic in low-temperature collisions CaH(${}^{2}\ensuremath{\Sigma}$) Li and Mg occurs at a slow rate despite the interactions. This unexpected result, which...

<italic>Cis</italic>–<italic>Trans</italic> isomerization of retinal induced by incoherent solar light. Shown are ground and excited-state diabatic potentials; the horizontal lines represent bright eigenstates (red), intermediate (blue), product (green). The inset: photoreaction efficiency <italic>vs</italic>. time with (red) without (blue) Fano coherences.

We develop a theoretical method for solving the quantum mechanical reactive scattering problem in presence of external fields based on hyperspherical coordinate description reaction complex combined with total angular momentum representation collisions fields. The allows us to obtain converged results chemical LiF+H→Li+HF an electric field. Our calculations demonstrate that, by inducing couplings between states different momenta, magnitudes <150 kV/cm give rise resonant and significant...

We present a theoretical study of the quantum dynamics energy transfer in model photosynthetic dimer excited by incoherent light and show that interplay between pumping phonon-induced relaxation, dephasing, trapping leads to emergence non-equilibrium stationary states characterized substantial coherences basis. obtain analytic expressions for these limits rapid dephasing electronic excitations small excitonic coupling chromophores. The are maximized regime where is compared rate. further...

Ergodicity, the central tenet of statistical mechanics, requires an isolated system to explore all available phase space constrained by energy and symmetry. Mechanisms for violating ergodicity are interest probing nonequilibrium matter protecting quantum coherence in complex systems. Polyatomic molecules have long served as a platform breaking vibrational transport. Here, we report observation rotational unprecedentedly large molecule, 12C60, determined from its icosahedral rovibrational...

We propose to sympathetically slow and cool polar molecules in a cold, low-density beam using laser-cooled Rydberg atoms. The elastic collision cross sections between atoms are large enough efficiently thermalize the even environment. Molecules traveling at $100\text{ }\text{ }\mathrm{m}/\mathrm{s}$ can be stopped under 30 collisions with little inelastic loss. Our method does not require photon scattering from generically applied complex species for applications precision measurement,...

We propose a new method for the direct and efficient evaluation of Felix Smith's lifetime Q matrix reactive scattering problems. Simultaneous propagation solution to set close-coupled equations together with its energy derivative allows one avoid common problems pertinent finite-difference approach. The procedure is implemented on code which employs hyperquantization algorithm Johnson-Manolopoulos [J. Comput. Phys. 13, 455 (1973); J. Chem. Phys 85, 6425 (1986)] obtain complete S observables....

We present a theory for rigorous quantum scattering calculations of probabilities chemical reactions atoms with diatomic molecules in the presence an external electric field. The approach is based on fully uncoupled basis set representation total wave function space-fixed coordinate frame, Fock–Delves hyperspherical coordinates, and adiabatic partitioning Hamiltonian reactive system. channel functions are expanded sets hyperangular corresponding to different reaction arrangements,...

We present a rigorous study of cold and ultracold collisions $\mathrm{Yb}\mathrm{F}(^{2}\ensuremath{\Sigma})$ molecules with He atoms in external electric magnetic fields based on an accurate calculation the interaction potential surface quantum theory atom-molecule scattering. analyze mechanisms collisional depolarization electron nuclear spins YbF demonstrate that rate constants for elastic inelastic are sensitive to magnitudes applied fields. Collisions heavy polar like may thus be easily...