A5072712752- Quantum Chromodynamics and Particle Interactions
- Particle physics theoretical and experimental studies
- Nuclear physics research studies
- High-Energy Particle Collisions Research
- Mechanical and Optical Resonators
- Atomic and Subatomic Physics Research
- Nuclear Physics and Applications
- Atomic and Molecular Physics
- Particle Accelerators and Free-Electron Lasers
- Superconducting Materials and Applications
- Particle accelerators and beam dynamics
- Quantum Information and Cryptography
- Electron and X-Ray Spectroscopy Techniques
- Advanced Chemical Physics Studies
- Advanced NMR Techniques and Applications
- Photonic and Optical Devices
- Magnetic Properties of Alloys
- Advanced MEMS and NEMS Technologies
- Physics of Superconductivity and Magnetism
- Quantum and electron transport phenomena
- Rare-earth and actinide compounds
- Neural Networks and Reservoir Computing
- Advanced Electrical Measurement Techniques
- Quantum, superfluid, helium dynamics
- Quantum Mechanics and Applications
Praevium Research (United States)
2025
National Institute of Standards and Technology
2017-2021
University of Colorado Boulder
1993-2021
Princeton University
2018
Georgetown University
2010
University of Massachusetts Amherst
1988-2005
Old Dominion University
2004
Istituto Nazionale di Fisica Nucleare, Sezione di Genova
2004
Massachusetts Institute of Technology
2003
Rutgers, The State University of New Jersey
2002-2003
We report results of an electron-beam-dump search for neutral particles with masses in the range 1 to 15 MeV and lifetimes \ensuremath{\tau} between ${10}^{\mathrm{\ensuremath{-}}14}$ ${10}^{\mathrm{\ensuremath{-}}10}$ s. No evidence was found such object. fule out existence any 1.8-MeV pseudoscalar boson \ensuremath{\tau}>8.2\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}15}$ s absorption cross section matter less than mb per nucleon, exclude...
Quantum entanglement of mechanical systems emerges when distinct objects move with such a high degree correlation that they can no longer be described separately. Although quantum mechanics presumably applies to all sizes, directly observing becomes challenging as masses increase, requiring measurement and control vanishingly small error. Here, using pulsed electromechanics, we deterministically entangle two drumheads 70 pg. Through nearly quantum-limited measurements the position momentum...
The authors program a superconducting circuit $i\phantom{\rule{0}{0ex}}n$ $s\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}u$ to operate as microwave circulator, or directional amplifier. compact lumped element can be directly integrated with other circuitry for nearly lossless routing and measurement of quantum signals. This work combines advanced understanding parametric-coupling physics innovative design engineering, fundamental impact on measurements plus direct...
We report on a precision measurement of the neutron spin structure function ${g}_{1}^{n}$ using deep inelastic scattering polarized electrons by ${}^{3}\mathrm{He}$. For kinematic range $0.014<x<0.7$ and $1<{Q}^{2}<17(\mathrm{GeV}/c{)}^{2}$, we obtain $\ensuremath{\int}{0.014}^{0.7}{g}_{1}^{n}(x)dx\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\ensuremath{-}0.036\ifmmode\pm\else\textpm\fi{}0.004(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.005(\mathrm{syst})$ at an average...
Nonreciprocal devices, in which electrical or optical signals travel one direction only, are essential for telecommunication and quantum applications, but they often both lossy bulky to implement. A prototype device demonstrates nonreciprocity a microwave optomechanical circuit that allows dynamic isolation control while avoiding the need large magnetic fields.
New measurements are reported on the deuteron spin structure function g_1^d. These results were obtained from deep inelastic scattering of 48.3 GeV electrons polarized deuterons in kinematic range 0.01 < x 0.9 and 1 Q^2 40 (GeV/c)^2. first high dose electron data using lithium deuteride (6Li2H) as target material. Extrapolations performed to obtain moments g_1^d, including Gamma_1^d, net quark polarization Delta Sigma.
We have measured the spin structure functions g2p and g2d virtual photon asymmetries A2p A2d over kinematic range 0.02⩽x⩽0.8 0.7⩽Q2⩽20GeV2 by scattering 29.1 32.3 GeV longitudinally polarized electrons from transversely NH3 6LiD targets. Our g2 approximately follows twist-2 Wandzura–Wilczek calculation. The twist-3 reduced matrix elements d2p d2n are less than two standard deviations zero. data inconsistent with Burkhardt–Cottingham sum rule if there is no pathological behavior as x→0....
The deuteron magnetic form factor B(${Q}^{2}$) has been measured at momentum transfers ${Q}^{2}$=1.21, 1.49, 1.61, 1.74, 1.98, 2.23, 2.48, 2.53, and 2.77 (GeV/c${)}^{2}$ the Stanford Linear Accelerator Center by detection of electrons backscattered 180\ifmmode^\circ\else\textdegree\fi{} in coincidence with recoiling deuterons 0\ifmmode^\circ\else\textdegree\fi{}. data for are found to decrease rapidly from ${Q}^{2}$=1.2 2 (GeV/c${)}^{2}$, then rise a secondary maximum around ${Q}^{2}$=2.5...
We present a new optomechanical device where the motion of micromechanical membrane couples to microwave resonance three-dimensional superconducting cavity. With this architecture, we realize ultrastrong parametric coupling, coupling rate not only exceeds dissipation rates in system but also rivals mechanical frequency itself. In regime, interaction induces splitting between hybridized normal modes that reaches 88% bare frequency, limited by fundamental instability. The thermal decoherence...
The structure and the degree of isospin mixing for ${1}^{+}$ levels in $^{12}\mathrm{C}$ at 12.71 MeV ($T=0$) 15.11 ($T=1$) are determined from measured 180\ifmmode^\circ\else\textdegree\fi{}-electron-scattering form factors. resulting charge-dependent isospin-mixing matrix element ranges 130 to 165 keV depending on theoretical model isoscalar factor.
Cross sections for electron elastic scattering from $_{19}^{39}\mathrm{K}$ and $_{20}^{40}\mathrm{Ca}$ are given the momentum-transfer range 0.6 to 3.4 ${\mathrm{fm}}^{\ensuremath{-}1}$. The data were analyzed by means of a phase-shift code using phenomenological Fermi charge distributions modified with small undulations. difference $^{39}\mathrm{K}$ $^{40}\mathrm{Ca}$ has been compared $1{d}_{\frac{3}{2}}$ proton distribution other nuclear models.
The measurement of a quantum system is often performed by encoding its state in single observable light field. efficiency this can be reduced loss or excess noise on the way to detector. Even \textit{quantum-limited} detector that simultaneously measures second non-commuting would double output noise, therefore limiting $50\%$. At microwave frequencies, an ideal achieved noiselessly amplifying information-carrying quadrature field, but has remained experimental challenge. Indeed, while...
Magnetic excitations in $^{12}\mathrm{C}$ have been measured by inelastic electron scattering at backward angles for momentum transfers between $q=0.5 \mathrm{and} 3.3$ ${\mathrm{fm}}^{\ensuremath{-}1}$. Data $M1$, $M2$, $M3$, and $M4$ transitions are compared to shell model calculations. In general, the excitation energies reasonably predicted, as transfer dependences of form factors. However, factor magnitudes often exceed measurements factors more than 2. Candidates ${2}^{\ensuremath{-}}$...
The act of observing a quantum object fundamentally perturbs its state, resulting in random walk toward an eigenstate the measurement operator. Ideally, is responsible for all dephasing state. In practice, imperfections apparatus limit or corrupt flow information required feedback protocols, effect quantified by efficiency. Here we demonstrate efficient superconducting qubit using nonreciprocal parametric amplifier to directly monitor microwave field readout cavity. By mitigating losses...
Accurate measurements of the p(e,e?p)pi0 reaction were performed at Q^2=0.127(GeV/c)^2 in Delta resonance energy region. The experiments MIT-Bates Linear Accelerator used an 820 MeV polarized electron beam with out plane magnetic spectrometer system (OOPS). In this paper we report first simultaneous determination both TL and TL? (``fifth" or polarized) cross sections low Q^{2} where pion cloud contribution dominates quadrupole amplitudes (E2 C2). real imaginary parts transverse-longitudinal...
Elastic cross sections for electron scattering from $^{31}\mathrm{P}$ and $^{32}\mathrm{S}$ are given the momentum-transfer range 0.7 to 2.9 ${\mathrm{fm}}^{\ensuremath{-}1}$. The data were analyzed by means of a phase-shift code using phenomenological Fermi charge distributions modified with small undulations. difference has been compared $2{s}_{\frac{1}{2}}$ proton distribution other nuclear models.
Transverse form factors have been measured for elastic electron scattering from $^{10}\mathrm{B}$ and $^{11}\mathrm{B}$, as well the electroexcitation of 1.74-MeV (${J}^{\ensuremath{\pi}}$=${O}^{+}$, T=1) 5.17-MeV (${2}^{+}$, 1) levels $^{10}\mathrm{B}$. These results were utilized to determine radial shape 1${p}_{3/2}$ single-particle wave function within nuclear interior.
Quadrupole amplitudes in the ${\ensuremath{\gamma}}^{*}\stackrel{\ensuremath{\rightarrow}}{N}\ensuremath{\Delta}$ transition are associated with issue of nucleon deformation. A search for these small has been focus a series measurements undertaken at Bates/MIT by OOPS Collaboration. We report on results from $\mathrm{H}{(e,e}^{\ensuremath{'}}p){\ensuremath{\pi}}^{0}$ data obtained ${Q}^{2}=0.070(\mathrm{G}\mathrm{e}\mathrm{V}/{c)}^{2}$ and invariant mass $W=1155\mathrm{MeV}$ using...
Magnetic electron scattering cross sections for $^{25}\mathrm{Mg}$ and $^{93}\mathrm{Nb}$ have been measured by means of 180\ifmmode^\circ\else\textdegree\fi{} elastic at momentum transfers from 0.8 to 2.2 ${\mathrm{fm}}^{\ensuremath{-}1}$. The $M1$, $M3$, $M5$ form factors extracted the data agree with shell model Nilsson calculations over most transfer range. $M3$ factor is strongly suppressed respect $M1$ $M5$. relatively small quenching $M5$, $M7$, $M9$ are in good agreement a...
Measurements of the (2)H((-->)e,e(')p)n reaction were performed with out-of-plane magnetic spectrometers (OOPS) at MIT-Bates Linear Accelerator. The longitudinal-transverse, f(LT) and f(')(LT), transverse-transverse, f(TT), interference responses a missing momentum 210 MeV/c simultaneously extracted in dip region Q2 = 0.15 (GeV/c)(2). In comparison to models deuteron electrodisintegration, data clearly reveal strong effects relativity final-state interactions importance two-body...
Cross sections for inclusive electron scattering from aluminum have been measured at both forward and backward angles in the kinematic region near x=1 1.75${\mathit{Q}}^{2}$7 (GeV/c${)}^{2}$. The forward-angle data are good agreement with a recent calculation. Both calculation show scaling behavior ${\mathit{F}}_{2}$(\ensuremath{\xi},${\mathit{Q}}^{2}$)=\ensuremath{\nu}${\mathit{W}}_{2}$(\ensuremath{\xi},${\mathit{Q}}^{2}$) high ${\mathit{Q}}^{2}$ fixed values of Nachtmann variable...