Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:1602.06644 · Physical Review A

Spin-orbit states of neutron wave packets

J. Nsofini, Dusan Sarenac, Christopher J. Wood, David G. Cory, M. Arif, Charles W. Clark, M. G. Huber, Dmitry A. Pushin

Published Jul 13, 2016• 35 citations
arXivHTMLPDF

Abstract

We propose a method to prepare an entangled spin-orbit state between the spin and the orbital angular momenta of a neutron wave packet. This spin-orbit state is created by passing neutrons through the center of a quadrupole magnetic field, which provides a coupling between the spin and orbital degrees of freedom. A Ramsey-fringe-type measurement is suggested as a means of verifying the spin-orbit correlations.

DOI
10.1103/physreva.94.013605

Related papers

Structured Waves: From Matter to Light

Dmitry A. Pushin, Dusan Sarenac, J. Nsofini +7 more

Neutrons are important probes of mater and quantum physics. They are particularly powerful at characterizing magnetic structures. In order to extend the applications of neutron physics as a quantum probes/sensors we have developed methods based on Quantum Information Processing for preparing structured waves such as orbital and spin-orbit states of neutrons. Such states may be prepared for the beam as a whole, or with reference to the coherence length of the neutron wavepacket, which is much smaller than the width of useful beams. I will describe experiments to prepare and characterize neutron beams with specific orbital and spin-orbit structure based on neutron interferometry and will show how we can apply these methods to other type of probes such as light.

Imaging and Applied Optics•Jan 1, 2018•1 citation

Optical generation and quantitative characterizations of electron-hole entanglement

Yu Shi

Using a method of characterizing entanglement in the framework of quantum field theory, we investigate the optical generation and quantitative characterizations of quantum entanglement in an electron-hole system, in presence of spin-orbit coupling, and especially make a theoretical analysis of a recent experimental result. Basically, such entanglement should be considered as between occupation numbers of single-particle basis states, and is essentially generated by coupling between different single-particle basis states in the second-quantized Hamiltonian. Interaction with two resonant light modes of different circular polarizations generically leads to a superposition of ground state and two heavy-hole excitonic states. When and only when the state is a superposition of only the two excitonic eigenstates, the entanglement reduces to that between two distinguishable particles, each with two degrees of freedom, namely, band index, as characterized by angular momentum, and orbit, as characterized by position or momentum. The band-index state, obtained by tracing over the orbital degree of freedom, is found to be a pure state, hence the band index and orbital degrees of freedom are separated in this state. We propose some basic ideas on spatially separating the electron and the hole, so that the entanglement of band indices, or angular momenta, is between spatially separated electron and hole.

arXiv:cond-mat/0307437•Physical Review A•Mar 31, 2004•3 citations

Twisting neutral particles with electric fields

Niels Geerits, Stephan Sponar

We demonstrate that spin-orbit coupled states are generated in neutral magnetic spin-1/2 particles traveling through an electric field. The quantization axis of the orbital angular momentum is parallel to the electric field; hence both longitudinal and transverse orbital angular momentum can be created. Furthermore, we show that the total angular momentum of the particle is conserved. Finally we propose a neutron optical experiment to measure the transverse effect.

arXiv:2007.03345•Physical Review A•Feb 8, 2021•15 citations

Neutron-state entanglement with overlapping paths

Stephen J. Kuhn, S. McKay, Jiazhou Shen +12 more

The development of direct probes of entanglement is integral to the rapidly expanding field of complex quantum materials.Here we test the robustness of entangled neutrons as a quantum probe by measuring the Clauser-Horne-Shimony-Holt contextuality witness while varying the beam properties.Specifically, we show that the mode entanglement of the spin and path subsystems of individual neutrons prepared in two different experiments using two different apparatuses persists even after varying the entanglement length, coherence length, and neutron energy difference of the paths.The two independent apparatuses acting as entangler-disentangler pairs are static-field magnetic Wollaston prisms and resonance-field radio-frequency flippers.Our results show that the spatial and energy properties of the neutron beam may be significantly altered without reducing the contextuality witness value below the Tsirelson bound, meaning that maximum entanglement is preserved.We also show that two paths may be considered distinguishable even when the path states significantly overlap.Therefore, we have shown that our experimental results are consistent with the distinguishable subsystem assumption down to a separation of less than 100 nm, proving entanglement and the contextual nature of reality on short length scales.This work is the key step in the realization of the modular, robust technique of entangled neutron scattering, which can extract entanglement information from a sample without the knowledge of the microscopic sample Hamiltonian: only semiquantitative knowledge of the correlation lengths of the relevant degrees of freedom and the timescales of the characteristic dynamics is required.

arXiv:2012.11786•Physical Review Research•Jun 22, 2021•19 citations

Simulating Decoherence of Neutron Wave Packets in Magnetic Fields

Martin Suda

Fluctuations of the magnetic field lead to a dephasing of polarized neutron wave packets and to an attenuation of the interference term of the Wigner distribution. It turns out that the Schrödinger equation can be solved exactly by using a constant space-dependent magnetic potential plus an arbitrary number of time-dependent cosine- and sine-shaped potentials with different frequencies and amplitudes. If the time oscillations are not resolved or if frequency fluctuations are taken into consideration, one can work out a procedure to take the damping characteristics of the interference term into account. An arbitrary statistical noise function can be constructed by Fourier's theorem. This potential leads to depolarization due to a loss of phase correlation. One can simulate the transition from coherence to decoherence which can be used in ongoing spin-echo and quantum state reconstruction experiments.

Fortschritte der Physik•Oct 1, 2001•0 citations

Generating Entanglement of Spin and Orbital Angular Momentum by Metasurfaces

Tomer Stav, Arkady Faerman, Elhanan Maguid +4 more

We design an experiment that uses a highly efficient dielectric metasurface to create entanglement on a single photon. The spin-orbit interaction mediated by the metasurface entangles the polarization and orbital angular momentum degrees of freedom.

Conference on Lasers and Electro-Optics•Jan 1, 2018•0 citations
We propose a method to prepare an entangled spin-orbit state between the spin and the orbital angular momenta of a neutron wave packet. This spin-orbit state is created by passing neutrons through the center of a quadrupole magnetic field, which provides a coupling between the spin and orbital degrees of freedom. A Ramsey-fringe-type measurement is suggested as a means of verifying the spin-orbit correlations.
Neutrons are important probes of mater and quantum physics. They are particularly powerful at characterizing magnetic structures. In order to extend the applications of neutron physics as a quantum probes/sensors we have developed methods based on Quantum Information Processing for preparing structured waves such as orbital and spin-orbit states of neutrons. Such states may be prepared for the beam as a whole, or with reference to the coherence length of the neutron wavepacket, which is much smaller than the width of useful beams. I will describe experiments to prepare and characterize neutron beams with specific orbital and spin-orbit structure based on neutron interferometry and will show how we can apply these methods to other type of probes such as light.
Using a method of characterizing entanglement in the framework of quantum field theory, we investigate the optical generation and quantitative characterizations of quantum entanglement in an electron-hole system, in presence of spin-orbit coupling, and especially make a theoretical analysis of a recent experimental result. Basically, such entanglement should be considered as between occupation numbers of single-particle basis states, and is essentially generated by coupling between different single-particle basis states in the second-quantized Hamiltonian. Interaction with two resonant light modes of different circular polarizations generically leads to a superposition of ground state and two heavy-hole excitonic states. When and only when the state is a superposition of only the two excitonic eigenstates, the entanglement reduces to that between two distinguishable particles, each with two degrees of freedom, namely, band index, as characterized by angular momentum, and orbit, as characterized by position or momentum. The band-index state, obtained by tracing over the orbital degree of freedom, is found to be a pure state, hence the band index and orbital degrees of freedom are separated in this state. We propose some basic ideas on spatially separating the electron and the hole, so that the entanglement of band indices, or angular momenta, is between spatially separated electron and hole.
The development of direct probes of entanglement is integral to the rapidly expanding field of complex quantum materials.Here we test the robustness of entangled neutrons as a quantum probe by measuring the Clauser-Horne-Shimony-Holt contextuality witness while varying the beam properties.Specifically, we show that the mode entanglement of the spin and path subsystems of individual neutrons prepared in two different experiments using two different apparatuses persists even after varying the entanglement length, coherence length, and neutron energy difference of the paths.The two independent apparatuses acting as entangler-disentangler pairs are static-field magnetic Wollaston prisms and resonance-field radio-frequency flippers.Our results show that the spatial and energy properties of the neutron beam may be significantly altered without reducing the contextuality witness value below the Tsirelson bound, meaning that maximum entanglement is preserved.We also show that two paths may be considered distinguishable even when the path states significantly overlap.Therefore, we have shown that our experimental results are consistent with the distinguishable subsystem assumption down to a separation of less than 100 nm, proving entanglement and the contextual nature of reality on short length scales.This work is the key step in the realization of the modular, robust technique of entangled neutron scattering, which can extract entanglement information from a sample without the knowledge of the microscopic sample Hamiltonian: only semiquantitative knowledge of the correlation lengths of the relevant degrees of freedom and the timescales of the characteristic dynamics is required.
Fluctuations of the magnetic field lead to a dephasing of polarized neutron wave packets and to an attenuation of the interference term of the Wigner distribution. It turns out that the Schrödinger equation can be solved exactly by using a constant space-dependent magnetic potential plus an arbitrary number of time-dependent cosine- and sine-shaped potentials with different frequencies and amplitudes. If the time oscillations are not resolved or if frequency fluctuations are taken into consideration, one can work out a procedure to take the damping characteristics of the interference term into account. An arbitrary statistical noise function can be constructed by Fourier's theorem. This potential leads to depolarization due to a loss of phase correlation. One can simulate the transition from coherence to decoherence which can be used in ongoing spin-echo and quantum state reconstruction experiments.