Sven Herrmann
A5072085911- Cold Atom Physics and Bose-Einstein Condensates
- Advanced Frequency and Time Standards
- Atomic and Subatomic Physics Research
- Quantum Mechanics and Applications
- Advanced X-ray Imaging Techniques
- Noncommutative and Quantum Gravity Theories
- Astrophysical Phenomena and Observations
- Particle Detector Development and Performance
- Geophysics and Sensor Technology
- Relativity and Gravitational Theory
- Quantum Information and Cryptography
- Radioactive Decay and Measurement Techniques
- Cosmology and Gravitation Theories
- Black Holes and Theoretical Physics
- Planetary Science and Exploration
- Gamma-ray bursts and supernovae
- Mechanical and Optical Resonators
- X-ray Spectroscopy and Fluorescence Analysis
- Quantum Electrodynamics and Casimir Effect
- Medical Imaging Techniques and Applications
- Pulsars and Gravitational Waves Research
- Astrophysics and Cosmic Phenomena
- Geophysics and Gravity Measurements
- Crystallography and Radiation Phenomena
- CCD and CMOS Imaging Sensors
Brookhaven National Laboratory
2020-2025
University of Bremen
2015-2024
SpaceTech (Germany)
2010-2024
Stanford University
2007-2024
Kavli Institute for Particle Astrophysics and Cosmology
2024
Institute for Applied Systems Technology Bremen
2014-2023
SLAC National Accelerator Laboratory
2013-2019
Technical University of Munich
2016
Linac Coherent Light Source
2014-2016
Universität Ulm
2015
Atom interferometers covering macroscopic domains of space-time are a spectacular manifestation the wave nature matter. Because their unique coherence properties, Bose-Einstein condensates ideal sources for an atom interferometer in extended free fall. In this Letter we report on realization asymmetric Mach-Zehnder operated with condensate microgravity. The resulting interference pattern is similar to one far field double slit and shows linear scaling time packets expand. We employ...
We present a test of the local Lorentz invariance post-Newtonian gravity by monitoring Earth's with Mach-Zehnder atom interferometer that features resolution up to $8\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}9}g/\sqrt{\mathrm{Hz}}$, highest reported thus far. Expressed within standard model extension (SME) or Nordtvedt's anisotropic universe model, analysis limits four coefficients describing at ppb level and three others, for first time, 10 ppm level. Using SME we explicitly...
The plasma dynamics of single mesoscopic Xe particles irradiated with intense femtosecond x-ray pulses exceeding ${10}^{16}\text{ }\text{ }\mathrm{W}/{\mathrm{cm}}^{2}$ from the Linac Coherent Light Source free-electron laser are investigated. Simultaneous recording diffraction patterns and ion spectra allows eliminating influence focal volume intensity particle size distribution. data show that for clusters illuminated pulses, highly charged ionization fragments in a narrow distribution...
The theory of general relativity describes macroscopic phenomena driven by the influence gravity while quantum mechanics brilliantly accounts for microscopic effects.Despite their tremendous individual success, a complete unification fundamental interactions is missing and remains one most challenging important quests in modern theoretical physics.The STE-QUEST satellite mission, proposed as medium-size mission within Cosmic Vision program European Space Agency (ESA), aims testing with high...
We report on a new test of Lorentz invariance performed by comparing the resonance frequencies two orthogonal cryogenic optical resonators subject to Earth's rotation over $\ensuremath{\sim}1\text{ }\mathrm{y}\mathrm{r}$. For possible anisotropy speed light $c$, we obtain ${\ensuremath{\Delta}}_{\ensuremath{\theta}}c/{c}_{0}=(2.6\ifmmode\pm\else\textpm\fi{}1.7)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}15}$. Within Robertson-Mansouri-Sexl (RMS) theory, this implies an isotropy...
We present up to 24-photon Bragg diffraction as a beam splitter in light-pulse atom interferometers achieve the largest splitting momentum space so far. Relative 2-photon processes used most sensitive interferometers, these large transfer splitters increase phase shift 12-fold for Mach-Zehnder (MZ) and 144-fold Ramsey-Bord\'e (RB) geometries. high visibility of interference fringes (up 52% MZ or 36% RB) long pulse separation times that are possible only atomic fountain setups. As atom's...
We present an improved laboratory test of Lorentz invariance in electrodynamics by testing the isotropy speed light. Our measurement compares resonance frequencies two orthogonal optical resonators that are implemented a single block fused silica and rotated continuously on precision air bearing turntable. An analysis data recorded over course one year sets limit anisotropy light \Delta c/c ~ 1 x 10^{-17}. This constitutes most accurate $c$ to date allows constrain parameters violating...
On August 22, 2014, the satellites GSAT-0201 and GSAT-0202 of European GNSS Galileo were unintentionally launched into eccentric orbits. Unexpectedly, this has become a fortunate scientific opportunity since onboard hydrogen masers allow for sensitive test redshift predicted by theory general relativity. In present Letter we describe an analysis approximately three years data from these including different clocks. For one determine parameter quantifying potential violation combined effects...
We present atom-interferometer tests of the local Lorentz invariance post-Newtonian gravity. An experiment probing for anomalous vertical gravity on Earth, which has already been performed by us, uses highest-resolution atomic gravimeter so far. The influence violation in electrodynamics is also taken into account, resulting combined bounds and electrodynamics. Expressed within standard model extension or Nordtvedt's anisotropic universe model, we limit twelve linear combinations seven...
Free-electron lasers (FELs) present new challenges for camera development compared with conventional light sources. At SLAC a variety of technologies are being used to match the demands Linac Coherent Light Source (LCLS) and support wide range scientific applications. In this paper an overview X-ray detector design requirements at FELs is presented various cameras in use described benefit users planning experiments or analysts looking data. Features operation CSPAD camera, which currently...
Do the laws of quantum physics still hold for macroscopic objects - this is at heart Schrödinger's cat paradox or do gravitation yet unknown effects set a limit massive particles? What fundamental relation between and gravity? Ground-based experiments addressing these questions may soon face limitations due to limited free-fall times quality vacuum microgravity. The proposed mission Macroscopic Quantum Resonators (MAQRO) overcome allow such questions. MAQRO harnesses recent developments in...
In contrast to light, matter-wave optics of quantum gases deals with interactions even in free space and for ensembles comprising millions atoms. We exploit these a degenerate gas as an adjustable lens coherent atom optics. By combining interaction-driven quadrupole-mode excitation Bose-Einstein condensate (BEC) magnetic lens, we form time-domain system. The focus is tuned by the strength lensing potential oscillatory phase quadrupole mode. placing at infinity, lower total internal kinetic...
Inertial sensors based on cold atoms have great potential for navigation, geodesy, or fundamental physics. Similar to the Sagnac effect, their sensitivity increases with space-time area enclosed by interferometer. Here, we introduce twin-lattice atom interferometry exploiting Bose-Einstein condensates. Our method provides symmetric momentum transfer and large areas in palm-sized sensor heads a performance similar present meter-scale devices.
We study a space-based gravity gradiometer based on cold atom interferometry and its potential for the Earth's gravitational field mapping. The instrument architecture has been proposed in [Carraz et al., Microgravity Science Technology 26, 139 (2014)] enables high-sensitivity measurements of gradients by using interferometers differential accelerometer configuration. present design including subsystems analyze mission scenario, which we derive expected performances, requirements sensor key...
We report relativity tests based on data from two simultaneous Michelson-Morley experiments, spanning a period of more than 1 yr. Both were actively rotated turntables. One (in Berlin, Germany) uses optical Fabry-Perot resonators made fused silica; the other Perth, Australia) microwave whispering-gallery sapphire resonators. Within standard model extension, we obtain limits Lorentz violation for electrons (5 coefficients) and photons (8) at levels down to ${10}^{\ensuremath{-}16}$, improved...
Bloch oscillations (i.e., coherent acceleration of matter waves by an optical lattice) and Bragg diffraction are integrated into light-pulse atom interferometers with large momentum splitting between the interferometer arms, hence enhanced sensitivity. Simultaneous both arms in same internal states suppresses systematic effects, simultaneously running a pair effect vibrations. Ramsey-Bord\'e using four such Bloch-Bragg-Bloch beam splitters exhibit 15% contrast at $24\ensuremath{\hbar}k$...
We report on a test of Lorentz invariance performed by comparing the resonance frequencies one stationary optical resonator and continuously rotating precision air bearing turntable. Special attention is paid to control rotation induced systematic effects. Within photon sector standard model extension, we obtain improved limits combinations 8 parameters at level few parts in ${10}^{\ensuremath{-}16}$. For previously least well known parameter find...
Abstract Future generations of global navigation satellite systems (GNSSs) can benefit from optical technologies. Especially clocks could back-up or replace the currently used microwave clocks, having potential to improve GNSS position determination enabled by their lower frequency instabilities. Furthermore, clock technologies—in combination with inter-satellite links—enable new architectures, e.g., synchronization distant references within constellation using time and transfer techniques....
We report on an improved test of the Universality Free Fall using a rubidium-potassium dual-species matter wave interferometer. describe our apparatus and detail challenges solutions relevant when operating potassium interferometer, as well systematic effects affecting measurement. Our determination E\"otv\"os ratio yields $\eta_{\,\text{Rb,K}}=-1.9\times10^{-7}$ with combined standard uncertainty $\sigma_\eta=3.2\times10^{-7}$.