Next generation cryogenic trap XII I XI X II HCI clocks III - PowerPoint PPT Presentation

Next generation cryogenic trap

XII I XI X II HCI clocks III IX IIII VIII V VII José R. Crespo López-Urrutia VI Max-Planck-Institut für Kernphysik

Table-top EBITs for PTB, Petra-III, Blaum division

HCI-clock laboratory at PTB

New MPIK-PTB cryogenic trap in operation • First device shipped to PTB, now operating • Week-long ion storage time • Ultra-low vibrations • Electric and magnetic shielding improved

Frequency metrology group at PTB Piet Schmidt Tobias Leopold Peter Micke Steven King + Lukas Spieß

Sympathetic resolved-sideband cooling

Quantum-logic spectroscopy on Ar 13+

Ar 13+ Zeeman structure Dirac + � � interactions Dirac + � � interactions + QED Landé � ‐ factors � ‐ factors from [Agababaev et al. arXiv:1812.06431] Dirac  measurement of ground ‐ and excited state g ‐ factors with <10 ppm  future: optical clock operation, isotope shifts, …

History of Ar 13+ frequency measurements new Penning trap measurement [S. Sturm et al. (MPIK), to be published] 2 P 3/2 441 nm 2 P 1/2 our current resolution: ~5 Hz Ar 13+ future

Quantum-logic spectroscopy on Ar 13+

State of the art: systematic uncertainty 1E ‐ 09 (estimated) systematic uncertainty HCI spectroscopy 1E ‐ 10 1E ‐ 11 1E ‐ 12 1E ‐ 13 1E ‐ 14 1E ‐ 15 1E ‐ 16 Cs clocks 1E ‐ 17 optical clocks 1E ‐ 18 1E ‐ 19 1950 1960 1970 1980 1990 2000 2010 2020 year

Frequency standards for VUV: Examples of forbidden transitions

M3 decay of Xe 26+ (Ni-like) 129,132 Xe LLNL X-ray microcalorimeter observation: • Transition energy: 1450 eV • Lifetime (15.06 ± 0.24) ms • Q-value 5 10 15 E. Träbert, P. Beiersdorfer, and G. V. Brown, Phys. Rev. Lett. 98 98, 263001 (2007)

Beryllium-like isoelectronic sequence 1s 2 2s2p 3 P 0 - 1s 2 2s 2 1 S 0 33 S 12+ 47,49 Ti 18+ 57 Fe 22+ E = 28.352 eV E = 43.169 eV E = 24.695 eV τ = 20 s τ = 10 s   = 28.72 nm = 43.7 nm  = 50.21 nm Q = 1.3 × 10 16 Q = 2.2 × 10 17 Q=6 × 10 15 Hyperfine-induced lifetime  1 s Measured: 1.8 s (S. Schippers)

Example: Nd-like isoelectronic sequence 10 30 60  =40 nm 10 29 50 Q ‐ value for 4f 13 5s ‐ 4f 14 transition 10 28 Q value � 10 28 10 27 40 Wavelength (nm) 10 26  =10 nm 10 25 30 Q value � 3×10 23 10 24 20 10 23 10 22 10 10 21 10 20 0 78 80 82 84 86 88 90 92 94 96 98 100 102 Atomic number Z Magnetic octupole VUV decays are very slow

High-harmonic generation at 100 MHz • Use HHG as light source for spectroscopy in XUV • Coherently transfer all comb modes from IR to XUV • Perform direct frequency comb spectroscopy (DIFCOS) • Challenge: Obtain enough intensity in XUV → use enhancement cavity Experiment by Janko Nauta, MPIK A Cingöz et al. Nature 482, 68-71 (2012) R. Jason Jones et al. Phys. Rev. Lett. 94, 193201 (2005)

The three-step model • Ionized electrons do not immediately leave their nuclei • Significant probability of electron returning to nucleus • Three steps: 1. Tunnel ionization in laser electric field 2. Acceleration of quasi-free electron in laser field 3. Recollision can lead to - recombination to ground state: emission of HHG-photons - elastic scattering: Above-threshold ionization - inelastic scattering: double ionization

High harmonic generation (HHG) max. 3.17 U p I p Tunneling ( I  10 14 ... 10 15 W/cm 2 ) Recollision and recombination Ponderomotive potential U p = I /4w 2

Why is the radiation harmonic? • At the collision all possible harmonics are generated • This process is periodic: Fourier transform yields harmonics E (t) t    n Photon picture HHG FUN  2  1 n q • Wave dynamics: Emission of specific harmonics 2x per cycle • Due to target isotropy => Not valid in few-cycle pulses!

General Setup for HHG Small tub Small tube with with fund fundamen amenta tal l harmonics harmonics noble gas noble gas wavelength length (tar (target) t) • Differential pumping needed • Long-term stability of enhancement resonator mirrors requires excellent vacuum • UHV setup needed

Intracavity high-harmonic generation (JILA) R. J. Jones et. al., PRL 94 94, 193201 (2005) (MPQ) C. Gohle et. al., Nature 436 436, 234 (2005) Image adapted from R. Jason Jones, University of Arizona

VUV frquency comb and HCI • In-vacuo enhancement cavity • In 15 μ m focus:  10 13 W/cm 2 • 100 MHz repetition rate VUV frequency comb EBIT Decceleration RF linear trap

Design of HHG focus Focus waist  15 μ m With 10 W frequency comb Enhancement to  10 13 W/cm 2 cylindrical incoupling mirror compensating astigmatism around focus region High-harmonics beams

Vibration suppression • Enhancement cavity mounted on high-stiffness titanium frame on optical table • Pump vibrations absorbed through mechanical low-pass filter, factor 10 reduction in amplitude

Temperature-controlled container for HHG-frequency comb

Modern slavery…

HHG in gas jet with differential pumping • For resonant enhancement, the length of the five-mirror ring- cavity is locked to the repetition rate of the frequency comb • Maximum enhancement of 100-200 is reached for exactly matched cavity lengths

Our first multi-photon test: Velocity-map imaging at 100 MHz repetition rate

Multi-photon ionization in focus • Multi-photon above-threshold ionization arises at similar intensities as high-harmonic generation • Fundamental IR at 1.2 eV • Velocity-map imaging of Xe, Kr, Ar with ionization potentials up to 15.6 eV • 16-photon signal observed • Horizontal and vertical laser polarization possible using intra- cavity waveplates With enhancement cavity locked, multiphoton ionization of gas atoms and molecules takes place at the focus (Janko Nauta et al.)

Polarization side-on With enhancement cavity locked on frequency comb, above-threshold multiphoton ionization of Xe atoms takes place at the focus with 2.5×10 12 W/cm 2 (Janko Nauta, Jan-Hendrik Oelmann, Alexander Ackermann, MPIK)

Next step: HHG differentially pumped jet

HHG in gas jet with differential pumping (Janko Nauta, Ronja Pappenberger, Jan-Hendrik Oelmann, MPIK)

What the PI wanted 1 st 2 nd 3 rd skimmer laser skimmers nozzle Triple differential pumping system for HHG gas nozzle (Janko Nauta, Ronja Pappenberger, Jan-Hendrik Oelmann, MPIK)

Next generation cryogenic trap • Cryogenic, XUHV • Ultra-low vibration • Superconducting high-Q RF resonator (Julian Stark, Christian Warnecke, Steffen Kühn, Michael Rosner

Advantages for fundamental studies • Whole new class of laser-accessible targets • Low sensitivity to DC and AC Stark shifts • Forbidden transitions suitable as frequency standards • High sensitivity to fine-structure constant • Large QED load • Optical transitions arising from, e. g.: •Fine structure in Be-like, B-like ions •HFS of ground state in H-like ions: Ho 66+ , Re 74+ , Tl 80+ , Pb 81+ , Bi 82+

Summary • HCI are ultra-stable, universal and reproducible probes of fundamental physics; effects magnified by Z -scaling laws • QED, relativistic as well as nuclear interactions and few- electron correlations in “tunable” admixtures •Whole new class of laser-accessible targets, with Z and ionic charge as parameters • Great variety of optical and EUV lines, fine and hyperfine transitions up to the highest charge states •Stable up to X-ray region •HCI frequency metrology enabled by sympathetic cooling, forbidden transitions suitable as frequency standards • Optical clocks for studies of α variation, Lorentz invariance benefit from insensitivity of HCI to perturbations

Strong overlap of electronic and nuclear wavefunctions

Precision isotope shifts Precision Isotope Shift Measurements in Calcium Ions Using Quantum Logic Detection Schemes Florian Gebert, Yong Wan, Fabian Wolf, Christopher N. Angstmann, Julian C. Berengut, and Piet O. Schmidt, Phys. Rev. Lett. 115, 053003 (2015)

Precision isotope shifts Probing New Long-Range Interactions by Isotope Shift Spectroscopy Julian C. Berengut, Dmitry Budker, Cédric Delaunay, Victor V. Flambaum, Claudia Frugiuele, Elina Fuchs, Christophe Grojean, Roni Harnik, Roee Ozeri, Gilad Perez, and Yotam Soreq Phys. Rev. Lett. 120, 091801 (2018) Probing new spin-independent interactions through precision spectroscopy in atoms with few electrons Cédric Delaunay, Claudia Frugiuele, Elina Fuchs, and Yotam Soreq Phys. Rev. D 96, 115002 (2017)

Comparison of electron density 10 1 Ca + 10 0 Ca 15+ 10 ‐ 1 10 ‐ 2 nucleus 10 ‐ 3 10 ‐ 4 10 ‐ 5 10 ‐ 6 10 ‐ 7 P 2 +Q 2 10 ‐ 8 10 ‐ 9 10 ‐ 10 10 ‐ 11 10 ‐ 12 10 ‐ 13 10 ‐ 14 10 ‐ 15 10 ‐ 16 10 ‐ 17 10 ‐ 18 10 ‐ 19 10 ‐ 20 10 ‐ 15 10 ‐ 14 10 ‐ 13 10 ‐ 12 10 ‐ 11 10 ‐ 10 10 ‐ 9 Radius (m) Even in light elements, in HCI the electron-nucleus overlap is enhanced by two orders of magnitude