Christian Sanner
University of Colorado Boulder
Elementary particlePauli exclusion principlePhysicsVortexIonDark matterExcited stateAtomPhysics beyond the Standard ModelAtomic physicsMaterials scienceAtomic clockSensitivity (control systems)Dimensionless quantityCondensed matter physicsComputational physicsFine-structure constantSpectroscopyBose–Einstein condensateMolecular physicsSymmetry (physics)FermionQuantum mechanicsDegenerate energy levelsFermi gasQuantum sensorOptical lattice
Publications 61
#1Thomas BilitewskiH-Index: 8
Last. Ana Maria Rey (NIST: National Institute of Standards and Technology)H-Index: 62
view all 9 authors...
The observation of Pauli blocking of atomic spontaneous decay via direct measurements of the atomic population requires the use of long-lived atomic gases where quantum statistics, atom recoil and cooperative radiative processes are all relevant. We develop a theoretical framework capable of simultaneously accounting for all these effects in a regime where prior theoretical approaches based on semi-classical non-interacting or interacting frozen atom approximations fail. We apply it to atoms in ...
#1A. CidrimH-Index: 5
#2A. Piñeiro OrioliH-Index: 1
Last. Ana Maria ReyH-Index: 62
view all 7 authors...
Dipole-dipole interactions lead to frequency shifts that are expected to limit the performance of next-generation atomic clocks. In this work, we compute dipolar frequency shifts accounting for the intrinsic atomic multilevel structure in standard Ramsey spectroscopy. When interrogating the transitions featuring the smallest Clebsch-Gordan coefficients, we find that a simplified two-level treatment becomes inappropriate, even in the presence of large Zeeman shifts. For these cases, we show a net...
1 CitationsSource
#1Christian SannerH-Index: 19
#2Lindsay SonderhouseH-Index: 11
Last. Jun YeH-Index: 126
view all 6 authors...
Spontaneous decay of an excited atomic state is a fundamental process that originates from the interaction between matter and vacuum modes of the electromagnetic field. The rate of decay can thus be engineered by modifying the density of final states of the joint atom-photon system. Imposing suitable boundary conditions on the electromagnetic field has been shown to alter the density of vacuum modes near the atomic transition, resulting in modified atomic decay rates. Here we report the first ex...
2 Citations
#1Richard Lange (German National Metrology Institute)H-Index: 6
#2Nils Huntemann (German National Metrology Institute)H-Index: 17
Last. Ekkehard Peik (German National Metrology Institute)H-Index: 39
view all 9 authors...
We compare two optical clocks based on the {^{2}S}_{1/2}(F=0)\ensuremath{\rightarrow}{^{2}D}_{3/2}(F=2)electric quadrupole (E2) and the {^{2}S}_{1/2}(F=0)\ensuremath{\rightarrow}{^{2}F}_{7/2}(F=3)electric octupole (E3) transition of {^{171}\mathrm{Yb}}^{+}and measure the frequency ratio {\ensuremath{\nu}}_{\mathrm{E}3}/{\ensuremath{\nu}}_{\mathrm{E}2}=0.932829404530965376(32) improving upon previous measurements by an order of magnitude. Using two caesium fountain clocks, we find ${\...
14 CitationsSource
#1Richard LangeH-Index: 6
#2Nils HuntemannH-Index: 17
Last. Ekkehard PeikH-Index: 39
view all 7 authors...
We introduce a scheme to coherently suppress second-rank tensor frequency shifts in atomic clocks, relying on the continuous rotation of an external magnetic field during the free atomic state evolution in a Ramsey sequence. The method retrieves the unperturbed frequency within a single interrogation cycle and is readily applicable to various atomic clock systems. For the frequency shift due to the electric quadrupole interaction, we experimentally demonstrate suppression by more than two orders...
3 CitationsSource
#2P. DelvaH-Index: 6
#3Ali Al-MasoudiH-Index: 12
Last. Peter WolfH-Index: 20
view all 54 authors...
We search for transient variations of the fine structure constant using data from a European network of fiber-linked optical atomic clocks. By searching for coherent variations in the recorded clock frequency comparisons across the network, we significantly improve the constraints on transient variations of the fine structure constant. For example, we constrain the variation to |δα/α| ~10^4 km) objects.
27 CitationsSource
#1Lindsay Sonderhouse (CU: University of Colorado Boulder)H-Index: 11
#2Christian Sanner (CU: University of Colorado Boulder)H-Index: 19
Last. Jun Ye (CU: University of Colorado Boulder)H-Index: 126
view all 9 authors...
Many-body quantum systems can exhibit a striking degree of symmetry unparallelled in their classical counterparts. In real materials SU(N) symmetry is an idealization, but this symmetry is pristinely realized in fully controllable ultracold alkaline-earth atomic gases. Here, we study an SU(N)-symmetric Fermi liquid of 87Sr atoms, where N can be tuned to be as large as 10. In the deeply degenerate regime, we show through precise measurements of density fluctuations and expansion dynamics that the...
15 CitationsSource
We carried out a 26-day comparison of five simultaneously operated optical clocks and six atomic fountain clocks located at INRIM, LNE-SYRTE, NPL and PTB by using two satellite-based frequency comparison techniques: broadband Two-Way Satellite Time and Frequency Transfer (TWSTFT) and Global Positioning System Precise Point Positioning (GPS PPP). With an enhanced statistical analysis procedure taking into account correlations and gaps in the measurement data, combined overall uncertainties in the...
9 CitationsSource
#1Thomas BilitewskiH-Index: 8
#2Lindsay SonderhouseH-Index: 11
Last. Jun YeH-Index: 126
view all 9 authors...