Search results for "Macroscopic quantum phenomena"
showing 6 items of 6 documents
Pfaffian and fragmented states atν=52in quantum Hall droplets
2008
When a gas of electrons is confined to two dimensions, application of a strong magnetic field may lead to startling phenomena such as emergence of electron pairing. According to a theory this manifests itself as appearance of the fractional quantum Hall effect with a quantized conductivity at an unusual half-integer v=5/2 Landau level filling. Here we show that similar electron pairing may occur in quantum dots where the gas of electrons is trapped by external electric potentials into small quantum Hall droplets. However, we also find theoretical and experimental evidence that, depending on the shape of the external potential, the paired electron state can break down, which leads to a fragm…
Quantum Disorder in Macroscopic Systems of Interacting Atoms and Radiation Fields
1978
The linear interaction between a system of two-level atoms and an electromagnetic field can be described as taking place through a number of elementary acts in which photons are absorbed or emitted, while atoms change their states. It is conceivable that these processes tend to modify the original statistical properties characteristic of the atomic system and of the electromagnetic field at t = 0, when we assume that the interaction is “turned on”. The problem is of conceptual importance, and might become of practical importance in connection with laser processes in unusual ranges of frequency. In fact, it has recently received increasing attention in the case of one-photon interactions [1]…
Novel T-violation observable open to any decay channel at meson factories
2015
Two genuine Quantum phenomena: Entanglement and Filtering Measurement are at the origin of the first direct observation of Time-Reversal-Violation in the time evolution of the B neutral meson system by BaBar. The used meson transitions are directly connected to semileptonic and CP-eigenstate decay channels. We analyse the possibility of extending the observable asymmetries to more decay channels. We propose an alternative T-Violation Asymmetry in the meson factories which allows its opening to any pair of decay channels. The new asymmetry needs also the measurement of the time dependent total survival probability of the initial tagged states. By combining several asymmetries these total sur…
Roadmap on quantum nanotechnologies
2021
Quantum phenomena are typically observable at length and time scales smaller than those of our everyday experience, often involving individual particles or excitations. The past few decades have seen a revolution in the ability to structure matter at the nanoscale, and experiments at the single particle level have become commonplace. This has opened wide new avenues for exploring and harnessing quantum mechanical effects in condensed matter. These quantum phenomena, in turn, have the potential to revolutionize the way we communicate, compute and probe the nanoscale world. Here, we review developments in key areas of quantum research in light of the nanotechnologies that enable them, with a …
Direct Identification of Dilute Surface Spins on Al2O3 : Origin of Flux Noise in Quantum Circuits
2017
An on-chip electron spin resonance technique is applied to reveal the nature and origin of surface spins on Al2O3. We measure a spin density of 2.2×1017 spins/m2, attributed to physisorbed atomic hydrogen and S=1/2 electron spin states on the surface. This is direct evidence for the nature of spins responsible for flux noise in quantum circuits, which has been an issue of interest for several decades. Our findings open up a new approach to the identification and controlled reduction of paramagnetic sources of noise and decoherence in superconducting quantum devices.
The Dynamics of Perspective in Quantum Physics: An Analysis in the Context of Teacher Education
2021
Debates on the philosophical interpretations of quantum physics have motivated a renewed interest in how secondary and lower undergraduate students interpret quantum phenomena. In an attempt to contribute to this effort, this paper examines the dynamics of perspec tive in quantum physics in the context of teacher education. The goal of the study is to investigate how students (N = 36) from a Master's Degree in Secondary Education Teacher Training in Spain negotiate perspective as they participate in small-group discussions of quantum physics topics. This study focuses on the wave-particle duality, superposition of states, and the calculation of probabilities for two-state systems. The metho…