Day 3 Day 3 Day 3 Resonant photon excitation in EBIT Synchrotron - PowerPoint PPT Presentation

Day 3

Day 3

Day 3

Resonant photon excitation in EBIT • Synchrotron radiation (PETRAIII), • Free-electron lasers (LCLS) , provide X-rays with high power and energy resolution

Resonant photon excitation in EBITs Photon beams interact with trapped ions photoions LCLS, BESSY II, Petra III, lasers Visible M1 Soft X-ray photoionization FEL 800 eV Synchrotron 6 keV Ar 13+ Fe 14+ Fe 16+ Fe 24+ , 13 keV Kr 34+ Fluorescence photons Ge detector photon energy (keV) 7 6 5 6650 6660 6670 6680 6690 6700 1 10 100 1,000 Photon energy monochromator (eV) Photons on Ge-detector V. Mäckel et al., M. C. Simon et al., J. K. Rudolph et al., S. Bernitt et al., PRL 107 107 143002 PRL 105 105 183001 PRL 111, 103002 Nature 492 492, 225 (2011) (2010) (2012) (2013)

Search for a time-variation of with cold HCI |e  Compare transitions that   ) depend differently on α |g   • Sensitivity coefficient q ~relativistic contributions � • HCI extremely sensitive: Frequency metrology on forbidden transitions between nearly degenerate states (e. g., Ir 17+ , Pr 9+ )

Enhanced sensitivity to  variation

Configuration crossings with charge state Atoms and lowly Highly charged ions charged ions • Re-arrangements of orbital energies with charge state • Levels of different parity nearly degenerate at crossing • Highest sensitivity J. C. Berengut et al. , PRL 106 106, 210802 (2011)

Many ultra-stable M1 transitions available • M1 clock transitions in monovalent [panels (a) and (b)] and divalent (c) highly charged ions. • A particular choice of nuclear spins in panels (b) and (c) and hyperfine states forming clock transitions eliminates quadrupolar shifts. • Predicted fractional accuracies below the 10 − 20 –10 − 21 level for all common systematic effects, such as blackbody radiation, Zeeman, ac-Stark, and quadrupolar shifts. M1 Transitions in HCI as a Basis of Ultraprecise Optical Clocks, Yudin, Taichenachev and Derevianko, PRL 113 113, 233003 (2014)

Level crossings in Ir 17+ large positive q small q optical transitions large negative q Hg + : q ~ 52 200 cm ‐ 1 Ir 17+ : q ~ 740 000 cm ‐ 1 J. C. Berengut et al. , PRL 106 106, 210802 (2011)

Level crossings at Ir 17+ provide sensitivity • With increasing charge state, reordering of levels takes place • 4f levels go below 5s at Z ≈ 77 • Levels of opposite parity cross: 4f 12 5s 2 , 4f 13 5 s , 4f 14 • M1, E1, E2, M2, M3 transitions become possible. • Several long lived „ground states“ available.

Line identification through M1-scaling functions E(Z)=A+B*Z+C*Z 2 • Comparison between theoretical and experimental scalings yields identification Windberger et al., PRL 114 114, 150801 (2015)

Line identification through g -factor fits Magnetic field causes large Zeeman splitting providing an additional criterion for identification of the lines Windberger et al., PRL 114 114, 150801 (2015)

Comparison between theories * • Fock-space coupled cluster calculation (A. Borschevski) shows agreement with experimental result at a level suitable for identification. • Its deviations from experiment are smaller than the average separation between spectral lines (as given by the green band). Windberger et al., PRL 114 114, 150801 (2015) * Berengut et al. , PRL 106 106, (2011)

New data on 4f 14 , 4f 13 5s and 4f 12 5s 2 for Ir 17+ M2/E3 clock transition at 1417 nm Arrows: Black, identified M1 lines; magenta, tentatively identified E1; orange, inferred M2/E3 clock transition; gray , previously identified. Unconnected fine-structure levels taken from FSCC calculations. H. Bekker et al., in preparation

Pr 9+ : four valence electrons (Sn-like) • Trapped ions are protected from collisional quenching and offer extremely long lived transitions • They may have several “ground states” usable as qubits 5s 2 5p 2 3 P 1 t = 0.003 s l=351 nm t =58 s 5s 2 5p4f 3 F 2 l=424 nm 5s 2 5p4f 3 G 3 M1 M3 M3 t = 20 000 000 years! q = 43000 cm -1 l=475 nm 5s 2 5p 2 3 P 0 Courtesy of M. S. Safronova Highly charged ions: Optical clocks and applications in fundamental physics, M. G. Kozlov, M. S. Safronova, JRCLU, P. O. Schmidt, RMP 90 90, 045005 (2018)

Pr 9+ : The 5p-4f crossing Crossing of three configurations including same and opposite parities, M1 to M3 transitions available H. Bekker, J. Berengut, submitted

Comparison between theories Experimental determination of all involved levels with Ritz-Rydberg method plus Zeeman H. Bekker, J. Berengut, submitted

Hyperfine couplings change lifetimes Frequency of proposed 3 P 0 → 3 G 3 clock transition determined with accuracy sufficient for quantum-logic spectroscopy at ultra-high resolution H. Bekker, J. Berengut, submitted

Highly ‐ charged ions as probes for Δ� � � � Δ� • strong relativistic effects, � large ionization energies � (nm) System K  strong sensitivity to a change in � Sr 0.06 699 • need different electronic configurations Yb + E2 0.91 436  optical transitions near level crossings Yb + E3 ‐ 6 467 • hyperfine ‐ transitions sensitive to �� Hg + ‐ 2.9 281.5 Al + [J. Berengut et al. , Phys. Rev. Lett. 105 , 120801 (2010); 0.01 267 J. C. Berengut et al. , Phys. Rev. Lett. 106 , 210802 (2011); Ir 17+ T1 ‐ 20.6 ca. 267 J. C. Berengut et al. , Phys. Rev. Lett. 109 , 70802 (2012); J. C. Berengut et al. , EPJ Web of Conferences 57 , 2001 (2013); Ir 17+ T2 32.2 ca. 470 V. A. Dzuba et al. , Phys. Rev. A 86 , 54502 (2012); M. S. Safronova et al. , Phys. Rev. A 90 , 42513 (2014); Cf 16+ * T1 75 ca. 520 M. S. Safronova et al. , Phys. Rev. Lett. 113 , 30801 (2014); Cf 16+ * T2 ‐ 46 ca. 653 V. A. Dzuba et al. , Phys. Rev. A 91 , 22119 (2015); V. A. Dzuba et al. , arXiv:1508.0768 (2015); Th* D. K. Nandy and B. K. Sahoo, Phys. Rev. A 94 , (2016)] 8000 ca. 160 nuclear

State of the art in the field of HCI • X-ray photon energies 1.5 ppm • VUV photon energies 4 ppm • Optical photon energies 0.3 ppm • Lifetimes (ns… ms) 0.15 % • Natural linewidths X-rays: resolved Accuracy is 10 orders of magnitude lower than in frequency metrology Stone-age spectroscopy at the 10 -6 level

Coulomb crystals with HCI for optical clock Collaboration with PTB (Piet Schmidt): build an optical clock with an HCI. MPIK-PTB Collaboration, M. Schwarz, “Cryogenic Linear Paul Trap...”, Rev. Sci. Instrum. 83, 083115 (2012)

Laser cooling in Paul trap: Ion crystals • Ion crystals (Be + ) at T=5 mK sympathetically cool HCI HCI • T HCI =10 6 K 0.1 K • Doppler width reduction • Low polarizability of HCI suppresses black-body and HCI light shifts HCI • Improved clocks: search for time-variation of α •Cooling applicable to X-ray laser spectroscopy

CryPTEx: Cooling T ion down to 100 mK The “Cryogenic Paul Trap Experiment“ was designed for sympathetic laser cooling of highly charged and molecular ions Design, construction 2010 (M. Schwarz, F. Brunner), tests 2011, operation 2012 M. Schwarz et al. RSI (2012); O. O.Versolato et al., Hyperfine Int. (2013)

4K trap accessible for HCI injection Be Lasers HCI Lasers Built by MPIK Apprentice Mechanical He, H 2 Workshop • 16 access ports to 4K trap: lasers, imaging, atoms, ions • External ion sources + in-trap photoionization • Measured pressure 10 -15 mbar • “Effective” black-body radiation temperature ~7.6 K

Paul trap at 5 K Be ion crystals four ions cryogenic shields two ions ↔ 0.05 trap electrodes mm atomic beam spectroscopy laser cooling laser ion crystal spectroscopy laser imaging lens O.O.Versolato, et al. PRL (2013); A. K. Hansen et al, Nature (2014)

Effects of trapping and cooling conditions Cold Be + Coulomb crystal 1 Ar 13+ mixed phase Be + ion cloud 3 Ar 13+ liquid phase Be + ion cloud ~ 20 Ar 13+

Nice crystals

HCI identification by image analysis The single HCI (here Ar 13+ ) repels Be + ions and • produces a hole in the Coulomb crystal • Addressing a single ion in the trap with a focused beam is possible due to large separation. Lisa Schmöger et al., Science 347 347, 1233 (2015)

HCI cooling with a single Be + ion Lisa Schmöger et al., Science 347 347, 1233 (2015)

HCI production, deceleration, implantation Lisa Schmöger et al., Science 347 347, 1233 (2015)