About
I am the Chief Research Scientist at Aspen Quantum Consulting, a leading firm that…
Articles by Charles
Contributions
Activity
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¤ "The logical endpoint of this is turning Russia into Iran" - attributed to a Russian source, referring to comparable isolation of Russia from…
¤ "The logical endpoint of this is turning Russia into Iran" - attributed to a Russian source, referring to comparable isolation of Russia from…
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تشرّفت اليوم بمنحي جائزة الباحث العربي الملهم "جائزة عباده" لعام ٢٠٢٤، ضمن فعاليات المؤتمر الدولي التاسع لمعامل التأثير العربي المقام هذا العام في…
تشرّفت اليوم بمنحي جائزة الباحث العربي الملهم "جائزة عباده" لعام ٢٠٢٤، ضمن فعاليات المؤتمر الدولي التاسع لمعامل التأثير العربي المقام هذا العام في…
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¤ Not even Saxony escapes the eagle eye of our Gandalf https://lnkd.in/e8SmQyXS
¤ Not even Saxony escapes the eagle eye of our Gandalf https://lnkd.in/e8SmQyXS
Shared by Charles Clark
Experience
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ScienceCast.org
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Licenses & Certifications
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Quantum Mechanics and Quantum Computation
Coursera
Publications
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Efficiency of neural-network state representations of one-dimensional quantum spin systems
arXiv
Neural-network state representations of quantum many-body systems are attracting great attention and more rigorous quantitative analysis about their expressibility and complexity is warranted. Our analysis of the restricted Boltzmann machine (RBM) state representation of one-dimensional (1D) quantum spin systems provides new insight into their computational complexity. We define a class of long-range-fast-decay (LRFD) RBM states with quantifiable upper bounds on truncation errors and provide…
Neural-network state representations of quantum many-body systems are attracting great attention and more rigorous quantitative analysis about their expressibility and complexity is warranted. Our analysis of the restricted Boltzmann machine (RBM) state representation of one-dimensional (1D) quantum spin systems provides new insight into their computational complexity. We define a class of long-range-fast-decay (LRFD) RBM states with quantifiable upper bounds on truncation errors and provide numerical evidence for a large class of 1D quantum systems that may be approximated by LRFD RBMs of at most polynomial complexities. These results lead us to conjecture that the ground states of a wide range of quantum systems may be exactly represented by LRFD RBMs or a variant of them, even in cases where other state representations become less efficient. At last, we provide the relations between multiple typical state manifolds. Our work proposes a paradigm for doing complexity analysis for generic long-range RBMs which naturally yields a further classification of this manifold. This paradigm and our characterization of their nonlocal structures may pave the way for understanding the natural measure of complexity for quantum many-body states described by RBMs and are generalizable for higher-dimensional systems and deep neural-network quantum states.
Other authorsSee publication -
Experimental realization of neutron helical waves
Science Advances
Methods of preparation and analysis of structured waves of light, electrons, and atoms have been advancing rapidly. Despite the proven power of neutrons for material characterization and studies of fundamental physics, neutron science has not been able to fully integrate these techniques because of small transverse coherence lengths, the relatively poor resolution of spatial detectors, and low fluence rates. Here, we demonstrate methods that are practical with the existing technologies and show…
Methods of preparation and analysis of structured waves of light, electrons, and atoms have been advancing rapidly. Despite the proven power of neutrons for material characterization and studies of fundamental physics, neutron science has not been able to fully integrate these techniques because of small transverse coherence lengths, the relatively poor resolution of spatial detectors, and low fluence rates. Here, we demonstrate methods that are practical with the existing technologies and show the experimental achievement of neutron helical wavefronts that carry well-defined orbital angular momentum values. We discuss possible applications and extensions to spin-orbit correlations and material characterization techniques.
Other authorsSee publication -
Demonstration of Neutron Detection Utilizing Open Cell Foam and Noble Gas Scintillation
Applied Physics Letters
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Hysteresis in a quantized superfluid ‘atomtronic’ circuit
Nature
Atomtronics is an emerging interdisciplinary field that seeks to develop new functional methods by creating devices and circuits where ultracold atoms, often superfluids, have a role analogous to that of electrons in electronics. Hysteresis is widely used in electronic circuits—it is routinely observed in superconducting circuits and is essential in radio-frequency superconducting quantum interference devices. Furthermore, it is as fundamental to superfluidity (and superconductivity) as…
Atomtronics is an emerging interdisciplinary field that seeks to develop new functional methods by creating devices and circuits where ultracold atoms, often superfluids, have a role analogous to that of electrons in electronics. Hysteresis is widely used in electronic circuits—it is routinely observed in superconducting circuits and is essential in radio-frequency superconducting quantum interference devices. Furthermore, it is as fundamental to superfluidity (and superconductivity) as quantized persistent currents, critical velocity and Josephson effects. Nevertheless, despite multiple theoretical predictions, hysteresis has not been previously observed in any superfluid, atomic-gas Bose–Einstein condensate. Here we directly detect hysteresis between quantized circulation states in an atomtronic circuit formed from a ring of superfluid Bose–Einstein condensate obstructed by a rotating weak link (a region of low atomic density). This contrasts with previous experiments on superfluid liquid helium where hysteresis was observed directly in systems in which the quantization of flow could not be observed, and indirectly in systems that showed quantized flow. Our techniques allow us to tune the size of the hysteresis loop and to consider the fundamental excitations that accompany hysteresis. The results suggest that the relevant excitations involved in hysteresis are vortices, and indicate that dissipation has an important role in the dynamics. Controlled hysteresis in atomtronic circuits may prove to be a crucial feature for the development of practical devices, just as it has in electronic circuits such as memories, digital noise filters (for example Schmitt triggers) and magnetometers (for example superconducting quantum interference devices).
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High-resolution, vacuum-ultraviolet absorption spectrum of boron trifluoride
J. Chem. Phys.
BF3 is transparent in the ultraviolet, making it a viable gaseous scintillator for detecting neutrons.
Other authorsSee publication -
Atom-molecule equilibration in a degenerate Fermi gas with resonant interactions
J. Phys. B: At. Mol. Opt. Phys. 37, L351
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Phase diagrams for an ideal gas mixture of fermionic atoms and bosonic molecules
New J. Phys. 6, 123
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Longitudinal spin waves in a dilute Bose gas
Phys. Rev. Lett. 88, 230405
Patents
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Controller for and controlling neutron orbital angular momentum
Issued United States US Patent Application 20160360605
An orbital angular momentum (OAM) controller controls OAM of a plurality of neutrons and includes: a substrate; a first surface of the substrate; and a second surface of the substrate disposed opposingly across the substrate from the first surface and including a contoured shape. A process for controlling OAM of neutrons includes: subjecting an OAM controller to a plurality of neutrons; receiving the neutrons at a first surface of the OAM controller; transmitting the neutrons through the OAM…
An orbital angular momentum (OAM) controller controls OAM of a plurality of neutrons and includes: a substrate; a first surface of the substrate; and a second surface of the substrate disposed opposingly across the substrate from the first surface and including a contoured shape. A process for controlling OAM of neutrons includes: subjecting an OAM controller to a plurality of neutrons; receiving the neutrons at a first surface of the OAM controller; transmitting the neutrons through the OAM controller; and providing a phase shift .theta. to a wavefunction of neutrons transmitted through the OAM controller according to .theta..varies.T.sub.1+T.sub.2(.phi./2.pi.), wherein T.sub.1 is a first thickness of a substrate of the OAM controller, T2 is a second thickness of the substrate, and .phi. is an azimuthal angle of the substrate.
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Noble-gas-excimer detectors of slow neutrons
Issued United States 8,816,296
The present invention relates to apparatus and methods for use in highly sensitive and efficient neutron detection, that includes using trigger reactions to initiate far-ultraviolet (FUV) optical emissions. In some embodiments of the present invention, a method for the detection of slow neutrons includes absorption of a slow neutron with a high neutron capture-cross-section nucleus, decay of the compound nucleus into energetic particles, creation of excimers from the energetic particles…
The present invention relates to apparatus and methods for use in highly sensitive and efficient neutron detection, that includes using trigger reactions to initiate far-ultraviolet (FUV) optical emissions. In some embodiments of the present invention, a method for the detection of slow neutrons includes absorption of a slow neutron with a high neutron capture-cross-section nucleus, decay of the compound nucleus into energetic particles, creation of excimers from the energetic particles reacting with a background gas to form excimers, radiative decay of excimers resulting in emission of FUV radiation, and detection of the FUV radiation using an optical detector.
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Apparatus and method for detecting slow neutrons by Lyman alpha radiation
Issued United States 7,791,045
A method and apparatus for detecting slow neutrons by monitoring Lyman alpha radiation produced by the .sup.3He(n,tp) nuclear reaction induced by neutrons incident on a gas cell containing .sup.3He or a mixture of .sup.3He and other atoms and/or molecules. Such a method and/or apparatus includes the use of, for example, liquid .sup.3He and .sup.4He mixtures as a scintillation counter for the sensitive detection of neutrons using Lyman alpha radiation produced by the .sup.3He(n,tp) reaction. The…
A method and apparatus for detecting slow neutrons by monitoring Lyman alpha radiation produced by the .sup.3He(n,tp) nuclear reaction induced by neutrons incident on a gas cell containing .sup.3He or a mixture of .sup.3He and other atoms and/or molecules. Such a method and/or apparatus includes the use of, for example, liquid .sup.3He and .sup.4He mixtures as a scintillation counter for the sensitive detection of neutrons using Lyman alpha radiation produced by the .sup.3He(n,tp) reaction. The radiation can be detected with high efficiency with an appropriate photo-detector, or alternatively, it can be converted to radiation at longer wavelength by absorption in scintillation materials, with the radiation channeled to a photodetector. Because of the simplicity of the system and the fact that the radiation production mechanisms can be measured and/or calculated independently, the method and/or apparatus also has the potential for service as a calculable absolute detector.
Other inventorsSee patent
Projects
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NIST Digital Library of Mathematical Functions
- Present
Digital library of the special functions of mathematics. Free world-wide access online at http://dlmf.nist.gov Book version published by Cambridge University Press, ISBN-13: 978-0521192255 (paperback), 978-0521192255 (hardcover)
Other creatorsSee project -
Atomic Reference Data for Electronic Structure Calculations
- Present
Recommended values of atomic orbital and total energies for several variants of density functional theory.
Other creatorsSee project -
Cone beam neutron interferometry: from modeling to applications
https://arxiv.org/abs/2309.01787
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Experimental realization of neutron helical waves
Methods of preparation and analysis of structured waves of light, electrons, and atoms have been advancing rapidly. Despite the proven power of neutrons for material characterization and studies of fundamental physics, neutron science has not been able to fully integrate these techniques because of small transverse coherence lengths, the relatively poor resolution of spatial detectors, and low fluence rates. Here, we demonstrate methods that are practical with the existing technologies and show…
Methods of preparation and analysis of structured waves of light, electrons, and atoms have been advancing rapidly. Despite the proven power of neutrons for material characterization and studies of fundamental physics, neutron science has not been able to fully integrate these techniques because of small transverse coherence lengths, the relatively poor resolution of spatial detectors, and low fluence rates. Here, we demonstrate methods that are practical with the existing technologies and show the experimental achievement of neutron helical wavefronts that carry well-defined orbital angular momentum values. We discuss possible applications and extensions to spin-orbit correlations and material characterization techniques.
Other creators
Languages
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German
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Organizations
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Cosmos Club
Member
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Bangladesh Physical Society
Honorary Fellow and Life Member
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American Association for the Advancement of Science
Chair, Section B (Physics)
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American Physical Society
Chair, Division of Atomic, Molecular and Optical Physics
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Insitute of Physics
Member, Editorial Board, Journal of Physics B: Atomic, Molecular and Optical Physics
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Optica Worldwide, formerly Optical Society of America
Associate Editor, Optics Express
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¤ AI safety remains a hotspot https://lnkd.in/emudX87G
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Apparently the ancient Romans were building ConFlat-based cold atom systems! https://lnkd.in/gvRRSmN3
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¤ National Institute of Standards and Technology (NIST) lanches GenAI, a new program to assess generative AI technologies. https://lnkd.in/grYJ4-RM
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Those are Australian dollars, but they are still dollars! One wonders what PsiQuantum showed the Australian Government during due diligence.
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