A5007647469- Advanced Frequency and Time Standards
- Cold Atom Physics and Bose-Einstein Condensates
- Atomic and Subatomic Physics Research
- Advanced Fiber Laser Technologies
- Scientific Measurement and Uncertainty Evaluation
- Cardiovascular Syncope and Autonomic Disorders
- Spectroscopy and Laser Applications
- Quantum optics and atomic interactions
- Atomic and Molecular Physics
- Laser Design and Applications
- Advanced Chemical Physics Studies
- Radioactive Decay and Measurement Techniques
- Geodetic Measurements and Engineering Structures
- Quantum Information and Cryptography
- Geophysics and Sensor Technology
- Particle physics theoretical and experimental studies
- Network Time Synchronization Technologies
- Quantum Chromodynamics and Particle Interactions
- Advanced Electrical Measurement Techniques
- Quantum Mechanics and Applications
- Advanced Measurement and Metrology Techniques
- Semiconductor Lasers and Optical Devices
- Nonlinear Dynamics and Pattern Formation
- Spectroscopy and Quantum Chemical Studies
- Laser Material Processing Techniques
Physikalisch-Technische Bundesanstalt
2016-2025
Polish Botanical Society
2022
Heinrich Heine University Düsseldorf
2018
Leibniz University Hannover
2000-2010
Centre National de la Recherche Scientifique
2002-2004
Laboratoire Aimé Cotton
2003-2004
Abstract Leveraging the unrivalled performance of optical clocks as key tools for geo-science, astronomy and fundamental physics beyond standard model requires comparing frequency distant faithfully. Here, we report on comparison agreement two strontium at an uncertainty 5 × 10 −17 via a newly established phase-coherent link connecting Paris Braunschweig using 1,415 km telecom fibre. The remote is limited only by instability lattice themselves, with negligible contributions from transfer. A...
We present a laser system based on 48 cm long optical glass resonator. The large size requires sophisticated thermal control and optimized mounting design. A self-balancing was essential to reliably reach sensitivities acceleration of below Δν/ν<2×10(-10)/g in all directions. Furthermore, fiber noise cancellations from common reference point near the diode cavity mirror additional user points (Sr clock frequency comb) are implemented. Through comparison with other cavity-stabilized lasers...
We present a transportable optical clock (TOC) with Sr87. Its complete characterization against stationary lattice resulted in systematic uncertainty of 7.4×10−17, which is currently limited by the statistics determination residual light shift, and an instability 1.3×10−15/τ averaging time τ seconds. Measurements confirm that can be reduced to below design goal 1×10−17. To our knowledge, these are best uncertainties instabilities reported for any date. For autonomous operation, TOC has been...
Phase compensated optical fiber links enable high accuracy atomic clocks separated by thousands of kilometers to be compared with unprecedented statistical resolution. By searching for a daily variation the frequency difference between four strontium lattice in different locations throughout Europe connected such links, we improve upon previous tests time dilation predicted special relativity. We obtain constraint on Robertson--Mansouri--Sexl parameter $|\alpha|\lesssim 1.1 \times10^{-8}$...
We present improved constraints on the coupling of ultralight bosonic dark matter to photons based long-term measurements two optical frequency ratios. In these clock comparisons, we relate ^{2}S_{1/2}(F=0)↔^{2}F_{7/2}(F=3) electric-octupole (E3) transition in ^{171}Yb^{+} that ^{2}S_{1/2}(F=0)↔^{2}D_{3/2}(F=2) electric-quadrupole (E2) same ion, and ^{1}S_{0}↔^{3}P_{0} ^{87}Sr. Measurements first ratio ν_{E3}/ν_{E2} are performed via interleaved interrogation both transitions a single ion....
Abstract Ultrastable lasers are essential tools in optical frequency metrology enabling unprecedented measurement precision that impacts on fields such as atomic timekeeping, tests of fundamental physics, and geodesy. To characterise an ultrastable laser it needs to be compared with a similar performance, but suitable system may not available locally. Here, we report comparison two geographically separated lasers, over the longest ever reported metrological fibre link network, measuring 2220...
We present a scalable mixed-species Coulomb crystal clock based on the <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mrow><a:mmultiscripts><a:mrow><a:msub><a:mrow><a:mi>S</a:mi></a:mrow><a:mrow><a:mn>0</a:mn></a:mrow></a:msub></a:mrow><a:mprescripts/><a:none/><a:mrow><a:mn>1</a:mn></a:mrow></a:mmultiscripts></a:mrow><a:mo...
We have measured the absolute frequency of optical lattice clock based on 87Sr at PTB with an uncertainty using two caesium fountain clocks. This is close to accuracy today's best realizations SI second. The 5 s2 1S0 – 5s5p 3P0 transition in .13(17) Hz. Our result excellent agreement recent measurements performed different laboratories worldwide. improved total systematic our Sr standard by a factor five and reach , opening new prospects for ratio between clocks fundamental research, geodesy...
We have determined the frequency shift that blackbody radiation is inducing on 5s2 (1)S0-5s5p (3)P0 clock transition in strontium. Previously its uncertainty limited of strontium lattice clocks to 1×10(-16). Now associated with correction translates a 5×10(-18) relative at room temperature. Our evaluation based measurement differential dc polarizability two states and modeling dynamic contribution using this value experimental data for other atomic properties.
Since the pioneering work of Ramsey, atom interferometers are employed for precision metrology, in particular to measure time and realize second. In a classical interferometer, an ensemble atoms is prepared one two input states, whereas second left empty. this case, vacuum noise restricts interferometer standard quantum limit (SQL). Here, we propose experimentally demonstrate novel clock configuration that surpasses SQL by squeezing empty state. We create squeezed state containing average...
Optical clocks are not only powerful tools for prime fundamental research, but also deemed the re-definition of SI base unit second as they now surpass performance caesium atomic in both accuracy and stability by more than an order magnitude. However, important obstacle this transition has so far been limited reliability optical that made a continuous realization timescale impractical. In paper, we demonstrate how situation can be resolved based on clock established is superior to one even...
Optical lattice clocks with uncertainty and instability in the $10^{-17}$-range below have so far been demonstrated exclusively using fermions. Here, we demonstrate a bosonic optical clock $3\times 10^{-18}$ $2.0\times 10^{-17}$ accuracy, both values improving on previous work by factor 30. This was enabled probing transition an ultra-long interrogation time of 4 s, long coherence provided cryogenic silicon resonator, careful stabilization relevant operating parameters, at low atom density....
We search for transient variations of the fine structure constant using data from a European network fiber-linked optical atomic clocks. By searching coherent in recorded clock frequency comparisons across network, we significantly improve constraints on constant. For example, constrain variation alpha to <5*10^-17 transients duration 10^3 s. This analysis also presents possibility dark matter, mysterious substance hypothesised explain galaxy dynamics and other astrophysical phenomena that...
We review experimental progress on optical atomic clocks and frequency transfer, consider the prospects of using these technologies for geodetic measurements. Today, standards have reached relative inaccuracies below 10-17, opening new fields fundamental applied research. The dependence frequencies gravitational potential makes ideal candidates search deviations in predictions Einstein's general relativity, tests modern unifying theories development gravity field sensors. In this review, we...
We present non-standard optical Ramsey schemes that use pulses individually tailored in duration, phase, and frequency to cancel spurious shifts related the excitation itself. In particular, field their uncertainties of fringes can be radically suppressed (by 2-4 orders magnitude) comparison with usual method (using two equal pulses) as well single-pulse Rabi spectroscopy. Atom interferometers clocks based on two-photon transitions, heavily forbidden or magnetically induced spectroscopy...
An optical frequency standard based on an ensemble of neutral calcium atoms laser-cooled to $12\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{K}$ has been realized. By using ultracold atoms, one major previous source uncertainty, the residual Doppler effect, was reduced. We show that cold collisions contribute a negligible amount uncertainty. The influence temporal evolution phase laser pulses used interrogate clock transition measured and corrected for. at...
With 87Sr atoms confined in a one-dimensional optical lattice, the frequency of clock transition 5s2 1S0–5s5p 3P0 has been determined to be 429 228 004 229 872.9(5) Hz. The was measured with help femtosecond-frequency comb against one Physikalisch-Technische Bundesanstalt (PTB's) H-masers whose simultaneously by PTB Cs-fountain CSF1. Sr standard contributes fractional uncertainty 1.5 × 10−16 total uncertainty. agreement previous measurements at other institutes supports status this as...
We present an analysis of the different types noise from detection and interrogation laser in our strontium lattice clock. develop a model showing that setup quantum projection noise-limited is possible if more than 130 atoms are interrogated. Adding information about spectrum clock with sub-${10}^{\ensuremath{-}16}$ fractional frequency instability allows one to infer stability for modes operation. Excellent agreement experimental observations difference between two interleaved...
We have investigated the benefits of spin squeezed states for clocks operated with typical Brownian frequency noise-limited laser sources. Based on an analytic model closed servo-loop optical atomic clock, we can give quantitative predictions optimal clock stability a given dead time and noise. Our are in very good agreement numerical simulations servo-loop. find that usual cyclic Ramsey interrogation single ensembles time, even current most stable lasers squeezing only improve below...
We present a transportable ultra-stable clock laser system based on Fabry-Perot cavity with crystalline Al0.92Ga0.08As/GaAs mirror coatings, fused silica (FS) substrates, and 20 cm-long ultra-low expansion (ULE) glass spacer predicted thermal noise floor of mod σy = 7 × 10-17 in modified Allan deviation at one second averaging time. The has cylindrical shape is mounted 10 points. Its measured sensitivity the fractional frequency to acceleration for three Cartesian directions are 2(1) 10-12...
We report measurements of the transition frequencies $4s\phantom{\rule{0.2em}{0ex}}^{2}S_{1∕2}\ensuremath{-}4p\phantom{\rule{0.2em}{0ex}}^{2}P_{1∕2}$ and $4s\phantom{\rule{0.2em}{0ex}}^{2}S_{1∕2}\ensuremath{-}4p\phantom{\rule{0.2em}{0ex}}^{2}P_{3∕2}$ potassium isotopes 39, 40, 41 through an atomic beam experiment with a fractional uncertainty about $2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}$. For frequency calibration, fs-laser comb referenced to Cs clock was used. Compared...
We have quantified collisional losses, decoherence and the collision shift in a one-dimensional optical lattice clock on highly forbidden transition $^{1}S_{0}\mathrm{\text{\ensuremath{-}}}^{3}P_{0}$ at 698 nm with bosonic $^{88}\mathrm{Sr}$. were able to distinguish two loss channels: inelastic collisions between atoms upper lower state only. Based measured coefficients, we determine operation parameters which 1D-lattice $^{88}\mathrm{Sr}$ shows no degradation due fractional uncertainty...
We present precision measurements with MHz uncertainty of the energy gap between asymptotic and well bound levels in electronic ground state $X\text{ }{^{1}\ensuremath{\Sigma}}_{\text{g}}^{+}$ ${^{39}\text{K}}_{2}$ molecule. The molecules are prepared a highly collimated particle beam interrogated $\ensuremath{\Lambda}$-type excitation scheme optical transitions to long range close asymptote state, using electronically excited ${A\text{ }^{1}\ensuremath{\Sigma}}_{\text{u}}^{+}$ as...
Cryogenic single-crystal optical cavities have the potential to provide highest dimensional stability. We investigated long-term performance of an ultra-stable laser system which is stabilized a silicon cavity operated at 124 K. Utilizing frequency comb, compared hydrogen maser that referenced primary caesium fountain standard and $^{87}\mathrm{Sr}$ lattice clock PTB. With fractional instabilities $\sigma_y(\tau)\leq2\times10^{-16}$ for averaging times $\tau=60\mathrm{~s}$ $1000\mathrm{~s}$...