According to a well-known principle of quantum physics, the statistics of the outcomes of any quantum experiment are governed by a Positive-Operator-Valued Measure (POVM). In particular, for experiments designed to measure a specific physical quantity, like the time of a particle's first arrival at a surface, this principle establishes that if the probability distribution of that quantity does not arise from a POVM, no such experiment exists. Such is the case with the arrival time distributions proposed by Das and Dürr, due to the nature of their spin dependence.
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http://dx.doi.org/10.1038/s41598-024-53777-8 | DOI Listing |
Phys Chem Chem Phys
January 2025
Department of Chemical Engineering, Birla Institute of Technology and Science, Pilani, Rajasthan 333031, India.
Naphthalenediimide (NDI)-based donor-acceptor co-polymers with tunable electronic, optical, mechanical, and transport properties have shown immense potential as n-type conducting polymers in organic (opto)electronics. During the operation, the polymers undergo reduction at different charged states, which alters their (opto)electronic properties mainly due to the formation of the quasiparticles, polaron/bipolaron. The theoretical study based on quantum mechanical calculations can provide us with a detailed understanding of their (opto)electronic properties, which is missing to a great extent.
View Article and Find Full Text PDFAdv Mater
January 2025
Instituto de Ciencia Molecular (ICMol), Universitat de València, Catedrático José Beltrán 2, Paterna, 46980, Spain.
Twisting 2D van der Waals magnets allows the formation and control of different spin-textures, as skyrmions or magnetic domains. Beyond the rotation angle, different spin reversal processes can be engineered by increasing the number of magnetic layers forming the twisted van der Waals heterostructure. Here, pristine monolayers and bilayers of the A-type antiferromagnet CrSBr are considered as building blocks.
View Article and Find Full Text PDFJ Phys Condens Matter
January 2025
Department of Physics, University of Kerala, Karyavattom 695581, Thiruvananthapuram, Kerala, India.
The effects of Na doping on the structure magnetic, electric, and magnetoelectric properties of GaFeOwere studied. Rietveld refinement of the XRD data reveals the formation of a single-phase trigonal structure with no impurity on Na doping up to 50% and a significant increase in lattice strain with doping. FTIR and Raman analysis further supported the phase purity of the samples.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States.
Controlling the rate of electron spin relaxation in paramagnetic molecules is essential for contemporary applications in molecular magnetism and quantum information science. However, the physical mechanisms of spin relaxation remain incompletely understood, and new spectroscopic observables play an important role in evaluating spin dynamics mechanisms and structure-property relationships. Here, we use cryogenic magnetic circular dichroism (MCD) spectroscopy and pulse electron paramagnetic resonance (EPR) in tandem to examine the impact of ligand field (d-d) excited states on spin relaxation rates.
View Article and Find Full Text PDFMagn Reson Med
January 2025
School of Medicine and Health, Institute for Diagnostic and Interventional Neuroradiology, Technical University of Munich, Munich, Germany.
Purpose: In brain tumors, disruption of the blood-brain barrier (BBB) indicates malignancy. Clinical assessment is qualitative; quantitative evaluation is feasible using the K leakage parameter from dynamic susceptibility contrast MRI. However, contrast agent-based techniques are limited in patients with renal dysfunction and insensitive to subtle impairments.
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