The long-range order realized in the superfluid phases of (3)He leads to a nonlocal motion of spin in these phases. In the B phase the nonlocality manifests itself in the formation of a homogeneously precessing domain (HPD). This domain is formed under conditions of nuclear magnetic resonance. Within the domain spin precesses coherently-with the same frequency and phase even though the steady magnetic field can be nonuniform. Coherence of precession is maintained by the spin current carried by the condensate of Cooper pairs. The key experiments, revealing the main properties of the HPD and the underlying theory are briefly reviewed in this paper.
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http://dx.doi.org/10.1088/0953-8984/21/16/164202 | DOI Listing |
Z Med Phys
January 2025
Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland; Department of Radiology, Division of Radiological Physics, University Hospital Basel, Basel, Switzerland.
Purpose: This study aims to evaluate the feasibility of structural sub-millimeter isotropic brain MRI at 0.55 T using a 3D half-radial dual-echo balanced steady-state free precession sequence, termed bSTAR and to assess its potential for high-resolution magnetization transfer imaging.
Methods: Phantom and in-vivo imaging of three healthy volunteers was performed on a low-field 0.
Micron
December 2024
Department of Physics, Norwegian University of Science and Technology (NTNU), Trondheim 7491, Norway. Electronic address:
The separation of diffraction effects from phase contrast is a major challenge for differential phase contrast (DPC) imaging in scanning transmission electron microscopy (STEM). The application of electron beam precession has previously been proven successful in homogenizing the direct beam and improving the imaging of both long-range electric and magnetic fields. However, magnetic STEM-DPC imaging performed in a low magnification (LM) STEM mode suffers from significant aberrations of the probe forming lens and the consequent impediment of small precession angles.
View Article and Find Full Text PDFSoft Matter
November 2024
Experimentalphysik X, Physikalisches Institut, Universität Bayreuth, D-95440 Bayreuth, Germany.
We measure the dynamical behavior of colloidal singlets and dumbbells on an inclined magnetic moiré pattern, subject to a precessing external homogeneous magnetic field. At low external field strength single colloidal particles and dumbbells move everywhere on the pattern: at stronger external field strengths colloidal singlets and dumbbells are localized in generic locations. There are however nongeneric locations of flat channels that cross the moiré Wigner Seitz cell.
View Article and Find Full Text PDFJ Low Temp Phys
February 2024
Low Temperature Laboratory, Aalto University School of Science, Espoo, Finland.
We study the homogeneously precessing domain (HPD) in superfluid He-B in a regular continuous-wave nuclear magnetic resonance (CW NMR) experiment. Using Fourier analysis of CW NMR time traces, we identify several oscillation modes with frequency monotonically increasing with the frequency shift of the HPD. Some of these modes are localized near the cell walls, while others are localized in bulk liquid and can be interpreted as oscillations of -solitons.
View Article and Find Full Text PDFJ Comput Neurosci
August 2022
Laboratory of Systemic Organization of Neurons, Institute of Theoretical and Experimental Biophysics of Russian Academy of Sciences, Institutskya, 3, Pushchino, 124290, Moscow Region, Russian Federation.
Place cells are hippocampal neurons encoding the position of an animal in space. Studies of place cells are essential to understanding the processing of information by neural networks of the brain. An important characteristic of place cell spike trains is phase precession.
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