J. DiSciacca

Harvard University, Cambridge, Massachusetts, United States

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Publications (8)34.85 Total impact

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    J. DiSciacca · M. Marshall · K. Marable · G. Gabrielse
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    ABSTRACT: Previous measurements with a single trapped proton or antiproton detected spin resonance from the increased scatter of frequency measurements caused by many spin flips. Here a measured correlation confirms that individual spin transitions and states are detected instead. The high fidelity suggests that it may be possible to use quantum jump spectroscopy to measure the p and \pbar magnetic moments much more precisely.
    Physical Review Letters 03/2013; 110(14). DOI:10.1103/PhysRevLett.110.140406 · 7.51 Impact Factor
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    ABSTRACT: \DeclareRobustCommand{\pbar}{\HepAntiParticle{p}{}{}\xspace} \DeclareRobustCommand{\p}{\HepParticle{p}{}{}\xspace} \DeclareRobustCommand{\mup}{$\mu_{p}${}{}\xspace} \DeclareRobustCommand{\mupbar}{$\mu_{\pbar}${}{}\xspace} \DeclareRobustCommand{\muN}{$\mu_N${}{}\xspace For the first time a single trapped \pbar is used to measure the \pbar magnetic moment ${\bm\mu}_{\pbar}$. The moment ${\bm\mu}_{\pbar} = \mu_{\pbar} {\bm S}/(\hbar/2)$ is given in terms of its spin ${\bm S}$ and the nuclear magneton (\muN) by $\mu_{\pbar}/\mu_N = -2.792\,845 \pm 0.000\,012$. The 4.4 parts per million (ppm) uncertainty is 680 times smaller than previously realized. Comparing to the proton moment measured using the same method and trap electrodes gives $\mu_{\pbar}/\mu_p = -1.000\,000 \pm 0.000\,005$ to 5 ppm, for a proton moment ${\bm{\mu}}_{p} = \mu_{p} {\bm S}/(\hbar/2)$, consistent with the prediction of the CPT theorem.
    Physical Review Letters 01/2013; 110(13). DOI:10.1103/PhysRevLett.110.130801 · 7.51 Impact Factor
  • Acta Physica Polonica B, Proceedings Supplement 01/2013; 6(4):1093. DOI:10.5506/APhysPolBSupp.6.1093
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    J DiSciacca · G Gabrielse
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    ABSTRACT: The proton magnetic moment in nuclear magnetons is measured to be $\mu_p/\mu_N \equiv g/2 = 2.792\,846 \pm 0.000\,007$, a 2.5 ppm (parts per million) uncertainty. The direct determination, using a single proton in a Penning trap, demonstrates the first method that should work as well with an antiproton as with a proton. This opens the way to measuring the antiproton magnetic moment (whose uncertainty has essentially not been reduced for 20 years) at least $10^3$ times more precisely.
    Physical Review Letters 04/2012; 108(15):153001. DOI:10.1103/PhysRevLett.108.153001 · 7.51 Impact Factor
  • J. D. Wright · J. M. DiSciacca · J. M. Lambert
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    ABSTRACT: Using scaled-energy Stark spectroscopy, we report the observation of recurrences due to closed orbits, both geometric and diffractive, in the ν=0, R=1, nd Rydberg series of H2 (16<n<26) interacting with the ν=0, R=3 series (13<n<15). The data support the molecular closed-orbit theory prediction of diffractive trajectories due to inelastic scattering of the excited electron on the molecular core. We have made similar measurements in He, and a comparison between the recurrence properties of H2 and its united atom equivalent is given.
    Physical Review A 06/2010; 81(6). DOI:10.1103/PhysRevA.81.063409 · 2.99 Impact Factor
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    N Guise · J DiSciacca · G Gabrielse
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    ABSTRACT: The first one-proton self-excited oscillator (SEO) and one-proton feedback cooling are demonstrated. In a Penning trap with a large magnetic gradient, the SEO frequency is resolved to the high precision needed to detect a one-proton spin flip. This is after undamped magnetron motion is sideband-cooled to a 14 mK theoretical limit, and despite random frequency shifts (larger than those from a spin flip) that take place every time sideband cooling is applied in the gradient. The observations open a possible path towards a million-fold improved comparison of the antiproton and proton magnetic moments.
    Physical Review Letters 04/2010; 104(14):143001. DOI:10.1103/PHYSREVLETT.104.143001 · 7.51 Impact Factor
  • Li Leping · Gu Quanli · J. L. Knee · J. D. Wright · J. M. DiSciacca · T. J. Morgan
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    ABSTRACT: We report the observation of an electric quadrupole transition between the 4s{sup '}[1/2]â{sup o} and 3d[3/2]â{sup o} states in the spectrum of argon and use it in the first step of a scheme to excite Rydberg states. The initial identification of the transition is based on one-color, two-photon photoionization. A different experiment utilizing two-color, two-photon photoexcitation to Rydberg states confirms the identification. Despite the unavoidable background of one-color, two-photon photoionization, the latter experimental technique makes possible two-photon spectroscopy of Rydberg states using a resonant intermediate state populated by an electric quadrupole transition.
    Journal of the Optical Society of America B 03/2008; 25(3):334-337. DOI:10.1364/JOSAB.25.000334 · 1.81 Impact Factor
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    ABSTRACT: Recently, Rydberg states have been shown to be present in the plasma of an Argon glow discharge [1]. Properties of Rydberg states in electric fields contribute to the overall behavior of the ion-electron plasma, converting, for example, free electrons into Rydberg electrons and vise verse. We are investigating the role of Rydbergs in low-temperature plasmas. An experimental study is in progress to ascertain the properties of autoionizing Rydberg states of Argon and Xenon atoms in electric fields. The study involves the use of laser-fast-beam Stark spectroscopy. The initial state is metastable, formed by 5 keV charge transfer collisions of singly charged ions with atomic potassium vapor. Final states are Rydberg autoionizing states that lie between the lowest fine structure thresholds. Photoabsorption spectra will be presented along with Fourier transformed recurrence spectra that provides a semiclassical analysis of the dynamics of these states. Supported by NSF and IRCEP. [1] R. Mason et al, Phys. Rev. 68, 16408 (2003)