Science Daily May 2, 2024 If the metric of spacetime has a quantum mechanical description, its fluctuations at the Planck scale are expected to introduce non-unitary effects that are inconsistent with the standard unitary time evolution of quantum mechanics. Neutrinos interacting with such fluctuations would lose their quantum coherence, deviating from the expected oscillatory flavour composition at long distances and high energies. A team of researchers from several countries used atmospheric neutrinos detected by the IceCube South Pole Neutrino Observatory in the energy range of 0.5–10.0 TeV to search for coherence loss in neutrino propagation. They found no evidence of anomalous […]
Tag Archives: Quantum mechanics
Researchers achieve chemically controlled, reversible magnetic phase transition
Phys.org November 10, 2023 Researchers in China proposed a chemical means to reversibly control spin order of lactim–lactam tautomerization to reversibly modulate the magnetic phase transition in 2D organometallic lattices. They theoretically verified the proposal by designing several 2D organometallic frameworks with antiferromagnetic to ferrimagnetic spin order transformation modulated by lactim–lactam tautomerization on organic linkers. The transition originated from the change in spin states of organic linkers (from singlet to doublet) via tautomerization. Such a transition further switched materials’ electronic structures from normal semiconductors with zero spin polarization to bipolar magnetic semiconductors with valence and conduction band edges 100% spin […]
Zero-index metamaterials offer new insights into the foundations of quantum mechanics
Phys.org April 27, 2022 Most theoretical derivations of fundamental radiative processes rely on energetic considerations and detailed balance equations, but not on momentum considerations. An international team of researchers (USA – Harvard University, University of Pennsylvania, Belgium, Spain, Denmark) re-examined the foundations of quantum physics from the perspective of momentum and explored what happens when the momentum of light is reduced to zero. They theoretically demonstrated that momentum recoil, transfer momentum from the field to the atom and Doppler shift are inhibited in NZI materials. Fundamental radiative processes inhibition is also explained due to those momentum considerations inside three-dimensional NZI […]
First observation of the quantum boomerang effect
Nanowerk February 28, 2022 The boomerang effect is a disorder-induced behavior which inhibits transport of electrons turning what would otherwise be a conducting material into an insulator. An international team of researchers (USA – UC Santa Barbara, Brazil, France) reported experimental observation and characterization of this surprising quantum-mechanical phenomenon. They exposed a gas of ultracold lithium atoms to a phase-shifted pair of optical lattices to realize a “quantum kicked rotor,” a momentum-space realization of Anderson-localized matter. They observed the characteristic departure from and return to the origin that is the key signature of the boomerang effect. Detailed characterization revealed the […]
Does relativity lie at the source of quantum exoticism?
Phys.org April 2, 2020 In quantum mechanics inherent randomness happens without any cause. Randomness that appears in non-relativistic quantum theory tacitly respects relativity, for example, it makes instantaneous signaling impossible. An international team of researchers (Poland, Singapore, UK) argues that this is because the special theory of relativity can itself account for such a random behavior. They show that the full mathematical structure of the Lorentz transformation, the one which includes the superluminal part, implies the emergence of non-deterministic dynamics, together with complex probability amplitudes and multiple trajectories. This indicates that the connections between the two seemingly different theories are […]