Physics and Chemistry with Diatomic Molecules Near Absolute Zero Tanya Zelevinsky & ZLab Columbia University, New York
Pupin Labs @ Columbia E. Fermi I. I. Rabi
10 What is Ultracold? MK kk 7 6 5 4 3 2 K 1 0 mk mk -1-2 -3-4 -5-6 laser cooling of atoms
Beyond Cold Atoms Indirect molecule cooling optical or magnetic Direct molecule cooling buffer gas (sympathetic) cooling
Why Cold Molecules? atomic H spectrum molecular H 2 spectrum New science Quantum-state-controlled ultracold chemistry Dipolar quantum gases & many-body physics Enhancement of EDMs and parity violation New physics and 5 th force Fundamental constants & variations
Ultracold Diatomic Molecules Indirect molecule cooling Sr Sr Sr Sr
Tight Trapping: Optical Lattice Clocks l/2 standing wave of light create Sr 2 molecules 10-6 K optical probe trapping potential: ac Stark shift quantized motional states
Molecular Lattice Clock 88 Sr G. Reinaudi et al., PRL 109, 115303 (2012)
Science with Cold and Ultracold Molecules Ultracold chemistry Molecular clocks Table-top particle physics
Ultracold Chemistry Quantum-state selected reactants and products Bimolecular collisions AB + AB A 2 + B 2 Photoassociation A + A + g A * 2 Photodissociation A 2 + g A + A *
Ultracold Chemistry Quantum-state selected reactants and products Complete quantum state control of reverse collision Photodissociation A 2 + g A + A *
Ultracold Chemistry Quantum-state selected reactants and products Photodissociation Sr 2 + g Sr + Sr * The hydrogen atom of ultracold chemistry Experiment first-principles theory comparison
Ultracold Photodissociation Photofragment angular distribution V J = 2 J = 0 (J = 4; M = 1) Matter-wave interference dependence!
Photofragment Angular Distributions i = 1 i = 0 3 1 3 1 M. McDonald et al., Nature 535, 122 (2016)
Photofragment Angular Distributions i = 1 i = 0 Y 4 1 + e iδ Y 4 3 2 M. McDonald et al., Nature 535, 122 (2016)
Probing Reaction Barriers = 1 1 S + 3 P 1 = 0
PD light Probing Reaction Barriers Continuum (J = 1) 1 S + 3 P 1
M. McDonald et al., Nature 535, 122 (2016) Probing Reaction Barriers MHz MHz MHz b 20 J = 2 J = 0 I θ 1 + β 2 P 2 cos θ Continuum energy (MHz)
M. McDonald et al., Nature 535, 122 (2016) Probing Reaction Barriers MHz MHz MHz b 20 J = 2 J = 0 I θ 1 + β 2 P 2 cos θ barrier QC theory Continuum energy (MHz)
Field Control of Photodissociation Comparable energies at ~ 1 mk: Kinetic Barrier Zeeman
Field Control of Photodissociation Comparable energies at ~ 1 mk: Kinetic Barrier Zeeman M. McDonald et al., PRL, accepted
Field Control of Photodissociation B Sr 2 + g Sr + Sr * E PD Energy = 30 MHz = 1.5 mk Key point: Mixing of partial waves in the continuum M. McDonald et al., PRL, accepted
Science with Cold and Ultracold Molecules Ultracold chemistry Molecular clocks Table-top particle physics
Clocks 2 2 1 1 Electronic Vibrational Coherence time of 1 + 2 superposition Intrinsic Trap & environment
Two-Body Quantum Optics Identical nuclei Inversion symmetry superradiant S P + P S odd (u) subradiant X 2G 0 E1 0! S S even (g) S P P S even (g) M1 E2
Two-Body Quantum Optics Subradiance R 2 μ M1 μ E1 R λ 2 10 4 @ R = 100 a 0 Need 10 4 suppression of E1! Molecules B. Bussery-Honvault and R. Moszynski, Mol. Phys. 104, 2387 (2006)
W. Skomorowski et al., JCP 136, 194306 (2012) B. McGuyer et al., Nature Phys. 11, 32 (2015) Two-Body Subradiance R R
Subradiant Lifetime 5.5 ms molecule-light coherence time B. McGuyer et al., Nature Phys. 11, 32 (2015)
B. McGuyer et al., Nature Phys. 11, 32 (2015) Two-Body Subradiance Predissociation E R -4 R -2.5 Q > 3 10 12 R 2
Trap-Insensitive Spectroscopy Magic optical lattice trap create molecules 10-6 K optical probe
Dynamic polarizability a Trap-Insensitive Spectroscopy Magic optical lattice trap 2 1 Lattice wavelength Coherent superposition of 1 + 2
M. McDonald et al., PRL 114, 023001 (2015) Trap-Insensitive Spectroscopy Magic -lattice optical absorption spectrum red sideband carrier blue sideband
M. McDonald et al., PRL 114, 023001 (2015) Trap-Insensitive Spectrosopy G T
Dynamic polarizability Dynamic polarizability Trap-Insensitive Spectroscopy Magic optical lattice trap narrow resonance >100 nm Lattice wavelength Nonresonant crossing: Traditional choice; hard to find Resonant crossing: Heating/loss Lattice wavelength Resonant crossing: * No heating/loss! * Easy to find
Clock Based on Molecular Vibrations 1 Σ <30 THz
Dynamic polarizability Trap-Insensitive Spectroscopy Magic optical lattice trap narrow resonance 0.006 nm Lattice wavelength Resonant crossing: * No heating/loss! * Easy to find
Line width (MHz) Trap-Insensitive Spectroscopy Magic optical lattice trap 0.006 nm 600 coherence time 160 Hz
Trap-Insensitive Spectroscopy Magic optical lattice trap 160 Hz vibrational clock resonance 26 THz Q = 2 10 11 (fiber limited)
Science with Cold and Ultracold Molecules Ultracold chemistry Molecular clocks Table-top particle physics
New Mass-Dependent Forces V = GM2 r 1 + Ae r/λ Yukawa A < 10 21 @ 1 nm! Need state-of-the-art measurement of van der Waals interatomic force J. J. Lutz and J. M. Hutson, JMS 330, 43 (2016) M. Borkowski et al., arxiv:1612.03842
Molecular QED and 5 th force Born-Oppenheimer approximation E tot E el + E vib + E rot Beyond B-O adiabatic nonadiabatic relativistic finite-nuclear-size μ = m e Am μ 2 p α 2 μ, α 3 μ higher-order α 4 μ < 1 Hz r c /a 0 2 1 Σ 84 Sr, 86 Sr, 88 Sr dimers (6 combinations): fit up to 5 m-dependent corrections
Y. N. Pokotilovski, Phys. At. Nucl. 69, 924 (2006) Y. Kamiya et al., PRL 114, 161101 (2015) M. Bordag et al., Phys. Rep. 353, 1 (2001) M. Borkowski et al., J. Phys. Conf. Ser. 810, 012014 (2017) Strength of non-1/r 2 interaction log A Molecular QED and 5 th Force Neutron scattering 2006 Neutron scattering 2015 Van der Waals forces: 1-Hz Sr 2 spectroscopy projection Casimir forces log (l / m)
Zlab Current support: Columbia University, NSF, ONR, AFOSR, Templeton Foundation, Heising-Simons Foundation Theory: Mickey McDonald: APS DAMOP Doctoral Thesis Prize 2017 Robert Moszynski Iwona Majewska U. of Warsaw Geoff Iwata Stan Kondov Paul P. Konrad Wenz Alex S. Rees McNally Chih-Hsi Lee Kon Leung T. Z.