John Clauser

John Clauser

PhD Physics, Columbia Univ

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78
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Publications

Publications (78)
Chapter
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A survey of more than thirty quantum mechanics and quantum field theory textbooks and review articles reveals two distinctly different schools of thought regarding what quantum mechanics is. Indeed, these books are found to promote two very different formulations of quantum mechanics. One is formulated in laboratory space, while the other is formul...
Chapter
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Fifty years ago in 1964, John Bell [6], showed that deterministic local hidden-variables theories are incompatible with quantum mechanics for idealized systems. Inspired by his paper, Clauser, Horne, Shimony and Holt (CHSH) [12] in 1969 provided the first experimentally testable Bell Inequality and proposed an experiment to test it. That experiment...
Article
TMX (tandem mirror) experimental data on ambipolar potential control and on the accompanying electrostatic confinement are reported. In the radial core of the central cell, measurements of electrostatic potentials of 150 V which augment axial ion confinement are in agreement with predictions using the Maxwell-Boltzmann result. Central-cell ion conf...
Article
Data on field-reversal experiments in the neutral-beam-injected 2XIIB mirror machine are reported. The best result is an estimated field-reversal parameter ζ = ΔB/Bvac = 0.9 ± 0.2 with vacuum field strength Bvac = 4.35 kG. Experiments at higher field strength Bvac = 6.7 kG achieved ζ = 0.6 ± 0.1. Ion energy confinement nτEi for the Bvac = 6.7 kG ex...
Article
In the Tandem Mirror Experiment (TMX), the central-cell losses provide the warm unconfined plasma necessary to stabilize the drift-cyclotron loss-cone instability in the end cells. This places a theoretical limit on central-cell confinement, which is expressed as a limit on the end-cell to central-cell density ratio. As this density ratio increases...
Chapter
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Bell’s Theorem is one of the most profound results in physics of the twentieth century. Not only does it have a significant impact on natural philosophy and on the true meaning of quantum mechanics, it also has stimulated important and practical new research in quantum optics. In 1972 at the CQ03 Rochester conference, in response to a number of dis...
Article
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Bell's theorem represents a significant advance in understanding the conceptual foundations of quantum mechanics. The theorem shows that essentially all local theories of natural phenomena that are formulated within the framework of realism may be tested using a single experimental arrangement. Moreover, the predictions by those theories must signi...
Chapter
This chapter describes a particular form of a grating interferometer called the generalized Talbot-Lau (GTL) interferometer. The chapter first identifies a significant weakness (low throughput) of its progenitor form, separated beam envelope (SBE) interferometry, outlines the operating principles of the GTL interferometry, and shows how GTL interfe...
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We show that a Young's N slit interferometer can be used to factor the integer N. The device could factor four- or five-digit numbers in a practical fashion. This work shows how number theory may arise in physical problems, and may provide some insight as to how quantum computers can carry out factoring problems by interferometric means.
Article
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Summary form only given. We show that a Young's N-slit interferometer can be used to factor the integer N. When the number of slits is a product of integer factors, then an analysis of the diffraction pattern can be used to determine these factors. This work provides a simple example of number theory's appearance in physics, and can be helpful in u...
Chapter
Results of high flux atom interferometry experiments with potassium in generalized Talbot-Lou configurations are presented. The interferometer consists of a sequence of three planar vacuum-slit diffraction gratings, microfabricated from silicon nitride membranes. Interference fringes are sensed by measuring the transmission of atoms on a hot-wire a...
Article
Although interferometry's earliest and most familiar use is with photons, the discovery of matter-wave (deBroglie-wave) interference for electrons demanded the development of quantum mechanics. Since then, matter-wave interferometry has been performed with neutrons, Cooper electron-pairs, and most recently, with whole atoms and diatomic molecules....
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Atom de Broglie-wave interference fringes are revealed by their selective destruction. A thermal potassium beam is transmitted through a Talbot-Lau atom interferometer. Different fringe Fourier components resonate in the interferometer at different atomic velocities. The thermal velocity distribution averages and washes out the high-frequency compo...
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We describe the results of three sets of experiments to investigate producing cold slow collimated potassium atoms for applications with no access available for the introduction of counterpropagating laser light along the exiting atomic beam's axis. Velocity profiles are obtained via fluorescence from D1 excitation at perpendicular and nearly paral...
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A dc hot thermal and an ac-modulated cold slow potassium beam copropagate and pass through an atom de Broglie--wave interferometer, consisting of a sequence of three microfabricated diffraction gratings. Talbot-vonLau interference fringes are formed and sensed by measuring transmission with a hot wire as a function of grating position. The hot beam...
Article
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We present new methods and formulae for calculating the image amplitude and image spatial power spectral density produced by monochromatic point-source illumination of a finite (and/or infinite) periodic complex transmission grating. At specific finite-width resonances the image amplitude is seen to display periodic complex amplitude self-imaging o...
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In this note we provide a brief summary of vibration isolation techniques and their application to our neutral atom interferometry experiments at the UC Berkeley Physics Department. Naturally, the difficulty in achieving acceptable vibration isolation for any given experiment depends largely upon the noise sensitivity of the experiment. Since neutr...
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This note provides a brief summary of vibration isolation techniques and their application to our neutral atom interferometry experiments. Naturally, the difficulty in achieving acceptable vibration isolation for any given experiment depends largely upon the noise background of the laboratory, the noise generated by the experimental apparatus itsel...
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This note provides a brief summary of the use of Fourier-Fresnel imaging to neutral atom interferometry. In applications of neutral-atom interferometry not requiring the interferometer to have an open (multiply connected) topology, the use of this imaging has significant advantages, notably ease of alignment, significantly increased through-put flu...
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Upon looking at the various colossal interferometers, etc., discussed at this conference to test gravitational theory, one cannot avoid feeling that easier approaches exist. The use of low velocity, neutral atom matter waves in place of electromagnetic waves in sensitive inertial interferometer configurations is proposed. For applications, spacecra...
Article
This paper shows that matter-wave interferometers employing low-velocity neutral atoms can be used as inertial sensors with sensitivities that exceed those of conventional mechanical sensors and multiple circuit optical interferometers by many powers of ten. The energy and mass dependence of the phase shifts that are due to rotation and acceleratio...
Article
Thermal-barrier experiments in the Tandem Mirror Experiment Upgrade (TMX-U) are reported, along with progress made at the Lawrence Livermore National Laboratory in plasma confinement and central-cell heating. Thermal barriers in TMX-U improved axial confinement by two orders of magnitude over a limited range of densities, compared with confinement...
Conference Paper
Thermal-barrier experiments have been carried out in the Tandem Mirror Experiment-Upgrade (TMX-U). Measurements of nonambipolar and ambipolar radial transport show that these transport processes, as well as end losses, can be controlled at modest densities and durations. Central-cell heating methods using ion-cyclotron heating (ICH) and neutral-bea...
Conference Paper
We review two classes of plasma diagnostic techniques used in thermal-barrier tandem-mirror fusion experiments. The emphasis of the first class is to study mirror-trapped electrons at the thermal-barrier location. The focus of the second class is to measure the spatial and temporal behavior of the plasma space potential at various axial locations....
Article
The authors describe the x-ray diagnostics employed on the Tandem Mirror Experiment-Upgrade (TMX-U) to measure the x-ray emission from plasma locations where electron cyclotron radio frequency heating is applied. At each potential minimum of the TMX-U plasma, broadband spectra are obtained with NaI scintillation and cooled HPGe detectors that are c...
Article
We want to image the hot, mirror-confined electrons produced by electron cyclotron resonant heating in the end cells of the Tandem Mirror Experiment-Upgrade. Preliminary spectroscopic measurements with NaI(Tl) detectors indicate tail electron temperatures in the range of 100–300 keV. Our goal is to image x-rays in the energy range 10–200 keV, for p...
Article
In thermal-barrier experiments in the tandem mirror experiment upgrade axial confinement times of 50 to 100 ms have been achieved. During enhanced confinement we measured the thermal-barrier potential profile using a neutral-particle-beam probe. The experimental data agree qualitatively and quantitatively with the theory of thermal-barrier formatio...
Conference Paper
In our recent experiments on the TMX-U thermal-barrier device, we achieved the end plugging of axial ion losses up to a central cell density of n/sub c/ = 6 x 10/sup 12/ cm/sup -3/. During lower density experiments, we measured the axial potential profile characteristic of a thermal barrier and found an ion-confining potential greater than 1.5 kV a...
Conference Paper
Recent experiments on the TMX-U thermal barrier device at LLNL have achieved the end plugging of axial ion losses up to a central cell density of n/sub c/ = 2 x 10/sup 12/ cm. During these tests, the axial potential profile characteristic of a thermal barrier has been measured experimentally, indicating an ion-confining potential greater than 1.5 k...
Article
We report the results of X-ray emission measurements made at various plasma locations in the Tandem Mirror Experiment-Upgrade (TMX-U). By manipulating the electron and ion density profiles within the magnetic mirror end cells, a local minimum in the axial electrostatic potential creates a barrier that thermally isolates central cell electrons from...
Article
This paper describes results from the initial thermal barrier experiments in the Tandem Mirror Experiment-Upgrade (TMX-U). Strong end plugging has been produced using a combination of ECRH gyrotrons with sloshing ion beam injection. Plugging has been achieved with a central cell higher than that of the end plugs. In these low-density central cell e...
Conference Paper
This paper describes results from the Tandem Mirror Experiment-Upgrade (TMX-U). Mirror-confined electrons with 30 to 70 keV mean energy densities of 0.5 to 2.0 x 10/sup 12/ cm/sup -3/ and average betas of 3 to 5% are produced using electron-cyclotron resonant heating (ECRH). These results are consistent with an electron Fokker-Planck code. Improved...
Article
The power balance in the Tandem Mirror Experiment (TMX) is studied for several days of operation. Between them, these days typified the operating range of TMX. Examining the power balance on axis, it is found that 60% to 100% of the power is carried to the end walls by escaping central‐cell ions. Globally, these calculations account for 70% to 100%...
Article
Using the measured plasma densities and energies, the flow of power between the different particle species and regions of the tandem mirror experiment (TMX) is analyzed. The power flow is described by a simple classical model modified to include: (1) a halo of cool plasma that reduces end‐cell ion losses due to charge exchange on background gas, (2...
Article
The TMX-U data system is a general-purpose system for acquiring, analyzing, and output of TMX-U data, and can also apply to any pulsed controlled thermonuclear experiment. In its present implementation, it routinely acquires 3 Mbytes of data per shot at an average rate of one shot every 8 minutes. For increased throughput, the system uses 5 CPUs ac...
Article
Tandem-mirror plasma with sloshing-ion end plugs has been produced. Ion-velocity distribution functions are peaked at 47° to the magnetic field lines. Low-level ion-cyclotron fluctuations were detected at 1.8 times the plug-midplane frequency and with properties predicted by theory; they did not degrade plasma confinement in the plugs or central ce...
Article
An experimental study of radial transport in the Tandem Mirror Experiment is reported here. Plasma parameters were measured in a series of well-diagnosed plasma discharges. A negative electric current (80±40 A within a 30-cm radius) flowed to the end wall, implying an equal radial loss of plasma ions. The axial losses of plasma ions were 100 A from...
Article
This report summarizes the criteria and designs that were used for the two TMX Thomson-scattering systems. It describes the optical, mechanical, electronic, and computer analysis features of these installations. A brief discussion of general Thomson-scattering principles and sensitivity limits is given. Also included are some plasma electron temper...
Article
Experimental data from the Tandem Mirror Experiment (TMX) on ambipolar potential control and on the accompanying electrostatic confinement are reported. Results on the radial dependence of the central cell confining potential are given. Radial and axial particle losses as well as scaling of the central cell axial confinement are discussed.
Article
Results from the tandem mirror experiment (TMX) are described. Tandem mirror density and potential profiles are produced using end plug neutral beam injection and central cell gas fueling. TMX parameters are near those predicted theoretically. The end plug electron temperature is higher than in the comparably sized single mirror 2XIIB. Axial confin...
Article
Experimental results on ion cyclotron waves observed in the 2XIIB mirror machine are reviewed, and relevant theoretical work is discussed. The work reported generally substantiates the quasilinear diffusion model of mirror plasma confinement, but also suggests alternatives. The end loss current required by theory of the drift-cyclotron loss-cone (D...
Article
Results from the tandem mirror experiment are described. The configuration of axial density and potential profiles are created and sustained by neutral-beam injection and gas fueling. Plasma confinement in the center cell is shown to be improved by the end plugs by as much as a factor of 9. The electron temperature is higher than that achieved in o...
Article
Initial experimental results from the Tandem Mirror Experiment (TMX) are presented. Axial profiles of the plasma density and potential necessary for electrostatically enhanced confinement of the central-cell ions have been generated and sustained for the duration of neutral-beam injection. The resulting central-cell ion confinement against axial lo...
Article
A neutral-beam-sustained plasma in the 2XIIB mirror machine is stabilized by hydrogen gas ionized at one mirror. Peak plasma energy densities that exceed the energy density of the vacuum field (beta-circumflexequivalent8n/sub D/E-bar/sub D//B/sub vac//sup 2/approximately-greater-than1) are achieved with deuterons of average energy E-bar/sub D/appro...
Conference Paper
This paper reports results of 2XIIB neutral-beam injection experiments with plasma-stream stabilization. The plasma stream is provided either by a pulsed plasma generator located on the field lines outside the plasma region or by ionization of neutral gas introduced at the mirror throat. In the latter case, the gas is ionized by the normal particle...
Article
Full-text available
The results of an experiment are reported which measured the circular-polarization correlation of photons emitted in the 91 P 1→73 S 1→63 P 0 cascade of atomic mercury. The results appear to be in general agreement with the predictions of quantum theory. They are compared with the predictions by several inequalities derived for various alternatives...
Article
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An experiment was performed to search for the anomalous two-photon polarization correlation observed earlier by Holt and Pipkin using a cascade of atomic mercury. The experiment is a sensitive test of various aspects of the foundations of quantum mechanics. Although the present experimental arrangement differed only slightly from theirs, the anomal...
Article
The status of 2XIIB neutral beam injection experiments with stabilizing plasma is described. The stream suppresses ion-cyclotron fluctuations and permits denisty to 5 x ten to the 13th power /cu cm. The ion energy is 13 keV, and electron temperature reaches 140 eV. Plasma confinement increases with ion energy and n tau reaches 7 x ten to the 13th p...
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A broad class of theories, called "objective local theories," is defined, motivation for considering these theories is given, and experimental consequences of the class are investigated. An extension of previous analyses by Bell and by Clauser et al. shows that predictions of objective local theories and of quantum mechanics differ, and that an exp...
Article
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We have measured various coincidence rates between four photomultiplier tubes viewing cascade photons on opposite sides of dielectric beam splitters. This experimental configuration, we show, is sensitive to differences between the classical and quantum field-theoretic predictions for the photoelectric effect. The results, to a high degree of stati...
Article
In a popular quantum mechanics textbook one reads … “If we have some indications that classical wave theory is macroscopically correct, it is nevertheless clear that on the microscopic level only the corpuscular theory of light is able to account for typical absorption and scattering phenomena such as the photoelectric effect and the Compton effect...
Article
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The polarization correlation of photons emitted in an atomic cascade is treated in the framework of a general semiclassical radiation theory. The resulting predictions are contrasted with those of orthodox quantum-radiation theory. Experimental evidence is discussed which is in agreement with the latter theory, but excludes semiclassical theories i...
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We have measured the linear polarization correlation of the photons emitted in an atomic cascade of calcium. It has been shown by a generalization of Bell's inequality that the existence of local hidden variables imposes restrictions on this correlation in conflict with the predictions of quantum mechanics. Our data, in agreement with quantum mecha...
Article
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Scitation is the online home of leading journals and conference proceedings from AIP Publishing and AIP Member Societies
Article
Measuring microwave background intensity from spectra of interstellar molecules
Article
Perform a mathematical analysis of the tomography inversion problem for various configurations of a borehole gravity gradiometer. Our simulations typically call for logging a hole for about 4km of depth. Within the limits imposed by our presumed detector sensitivity, the device appears to be capable of measuring the 0.1 g/cm³ density in all rings...
Article
Full-text available
We present results of atom interferometry experiments in which spatial matter - wave interference is revealed by its selective destruction. A thermal potassium beam is transmitted through a velocity selective atom interferometer and detected. The interferometer is a sequence of three diffraction gratings. Interference fringes forming a Moire patter...
Article
We perform a mathematical analysis of the tomography inversion problem for various configurations of a borehole gravity gradiometer. Our simulations typically call for logging a hole for about 4km of depth. Within the limits imposed by our presumed detector sensitivity, the device appears to be capable of measuring the 0.1 g/cu cm density in all ri...
Article
The present status of tasks is: Task 1- Solution of tomography problem (completed qtrs. 1 and 2), Task 2- Study influence of vibrations (completed qtr. 3), Task 3- List of borehole imposed constraints (completed qtr.3 with update this qtr.), Task 4- Evaluate merits of various cooling schemes (completed this qtr.), Task 5- Specify magnet system requ...
Article
Full-text available
Results of atom interferometry experiments in generalized Talbot-vonLau configurations are presented. AC modulated D2 light from diode lasers is counter-directed on a thermal potassium beam. A pA AC current of cold, slow potassium atoms is extracted through a slit in a heated mirror, transmitted through an interferometer, and ionized by a hotwire....
Article
Thermal-barrier experiments have been carried out in the Tandem Mirror Experiment-Upgrade (TMX-U). Measurements of nonambipolar and ambipolar radial transport show that these transport processes, as well as end losses, can be controlled at modest densities and durations. Central-cell heating methods using ion-cyclotron heating (ICH) and neutral-bea...
Article
Naturally, as higher resolution and/or range is specified the reconstruction accuracy deteriorates. With too fine a resolution and/or at to great a range, the reconstructed density acquires sufficiently large error as to be meaningless. For a specified instrument accuracy we thereby determined the range and resolution limits of our instrument. Not...
Article
Results are presented for the following tasks completed this quarter: study the influence of vibrations of the logging tool itself; compile a list of borehole imposed constraints and tradeoffs for the design of a gadiometer; and formulate the requirements for a magnet system and determine the feasibility for use of a combination of permanent magnet...
Article
A series of experiments performed regarding the Bell inequality are briefly described. The results indicate that the notion of localized particle-like photons is consistent with experiment, and that such entities evidently do not split, at least with regard to their detectability. (JFP)
Article
The optimal species for experiments was earlier chosen as potassium, but this choice was reexamined in light of our current status and experience. The authors conclusion is that potassium still appears to be their best choice, although lithium may become preferable as laser technology evolves. Potassium's most significant difficulty is in producing...
Article
The tandem mirror device (TMX) exhibits gross stability to both MHD and microinstability modes. The end-cell plasmas provide the tandem with average minimum-B stability, while the efflux of plasma from the central cell maintains the end cells (plugs) at marginal stability to loss cone modes. For some operating conditions, a residual level of plug i...
Article
The research program is to study the spatial wave-like character of freely propagating neutral-atom matter-waves (deBroglie waves). To do so, we are constructing and using a neutral-atom matter-wave interferometer. An atomic beam will be decelerated and cooled by conventional laser spontaneous cooling. It will be extracted from the laser cooling ap...
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A theorem of Bell, proving that certain predictions of quantum mechanics are inconsistent with the entire family of local hidden-variable theories, is generalized so as to apply to realizable experiments. A proposed extension of the experiment of Kocher and Commins, on the polarization correlation of a pair of optical photons, will provide a decisi...
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From observations of interstellar optical absorption lines of CN, CH, and C${\mathrm{H}}^{+}$ we are able to impose upper limits, at three wavelengths, on the intensity of background radiation in the interstellar medium. These limits are consistent with the existence of thermal background radiation at a temperature of $\sim${}3\ifmmode^\circ\else\t...
Article
From observations of interstellar optical absorption lines of CN, CH, and C${\mathrm{H}}^{+}$ we are able to impose upper limits, at three wavelengths, on the intensity of background radiation in the interstellar medium. These limits are consistent with the existence of thermal background radiation at a temperature of \ensuremath{\sim}3\ifmmode^\ci...
Article
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Knowledge of the relaxation spectrum is important because (1) it provides an intrinsic characterization of the mechanical properties for linearly viscoelastic materials and (2) it offers a rational way to derive the coefficients for a Prony or Dirichlet series representation of the relaxation modulus of importance to some engineering analyses. A nu...
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DOI:https://doi.org/10.1103/PhysRevLett.16.819