Superradiant Spin-Flip Radiative Emission of a Spin-Polarized Free-Electron Beam

Gover, A.

doi:10.1103/physrevlett.96.124801

Cited by 9 publications

(14 citation statements)

References 17 publications

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“…This magnetic spontaneous emission rate is much weaker than the usual atomic spontaneous emission rate, and is significantly harder to detect, see [30]. The equations in (47) can now be written:…”

Section: Relaxation and Concurrencementioning

confidence: 99%

Loss of spin entanglement for accelerated electrons in electric and magnetic fields

Doukas

Hollenberg

2009

Phys. Rev. A

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Using an open quantum system we calculate the time dependence of the concurrence between two maximally entangled electron spins with one accelerated uniformly in the presence of constant electric and magnetic fields and the other at rest and isolated from fields. We find at high Rindler temperature the proper time for the entanglement to be extinguished is proportional to the inverse of the acceleration cubed.

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Section: Relaxation and Concurrencementioning

confidence: 99%

Loss of spin entanglement for accelerated electrons in electric and magnetic fields

Doukas

Hollenberg

2009

Phys. Rev. A

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“…It can be easily checked that for a neutral particle with a magnetic moment only and for an ideally conducting surface, the resultant formula coincides with Eq. (8).…”

Section: Radiation Field For Tr From Charge + Intrinsic Magnetic Mmentioning

confidence: 99%

“…There are several obstacles to this measurement. On the purely experimental side, a "no-win" situation: the PR intensity is, roughly speaking, larger for soft photons, especially in the coherent regime of emission (see e.g., [8]), but the relative contribution of the spin-induced magnetic moment is attenuated by ω/E e , where ω and E e are the photon energy and the electron energy, respectively. However even putting aside this experimental difficulty, there is a deeper problem of separating the spin-induced magnetic moment contribution to PR from the quantum recoil effects, which are of the same order (this fact was ignored in the analysis of Ref.…”

mentioning

confidence: 99%

“…However even putting aside this experimental difficulty, there is a deeper problem of separating the spin-induced magnetic moment contribution to PR from the quantum recoil effects, which are of the same order (this fact was ignored in the analysis of Ref. [8]). Indeed, in the macroscopic quasiclassical treatment of PR, one assumes that the particle trajectory stays unperturbed by the radiation.…”

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confidence: 99%

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Polarization radiation of vortex electrons with large orbital angular momentum

Иванов

Karlovets

2013

Phys. Rev. A

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Vortex electrons, -freely propagating electrons whose wavefunction has helical wavefronts, -could become a novel tool in the physics of electromagnetic radiation. They carry a non-zero intrinsic orbital angular momentum (OAM) with respect to the propagation axis and, for 1, a large OAM-induced magnetic moment, µ ≈ µB (µB is the Bohr magneton), which influences the radiation of electromagnetic waves. Here, we consider in detail the OAM-induced effects by such electrons in two forms of polarization radiation, namely in Cherenkov radiation and transition radiation. Thanks to the large , we can neglect quantum or spin-induced effects, which are of the order of ω/Ee 1, but retain the magnetic moment contribution ω/Ee 1, which makes the quasiclassical approach to polarization radiation applicable. We discuss the magnetic moment contribution to polarization radiation, which has never been experimentally observed, and study how its visibility depends on the kinematical parameters and the medium permittivity. In particular, it is shown that this contribution can, in principle, be detected in azimuthally non-symmetrical problems, for example when vortex electrons obliquely cross a metallic screen (transition radiation) or move nearby it (diffraction radiation). We predict a left-right angular asymmetry of the transition radiation (in the plane where the charge radiation distributions would stay symmetric), which appears due to an effective interference between the charge radiation field and the magnetic moment one. Numerical values of this asymmetry for vortex electrons with Ee = 300 keV and = O(100 − 1000) are O(0.1 − 1%), and we argue that this effect could be detected with existing technology. The finite conductivity of the target and frequency dispersion play the crucial roles in these predictions.

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“…18 The system then returns to equilibrium by emitting a single burst of photons at a wavelength corresponding to the Zeeman energy gap. 19 Although the magnetodipole emission rate of a single spin is quite small, the coherent spontaneous emission of a large number of spins by a crystal of magnetic molecules [20][21][22] has produced microwave bursts peaking at a few tens of femtowatts. 23,24 Other magnetodipole microwave sources include notably magnetic dust in interstellar clouds, which is responsible for the so-called cosmic microwave foreground.…”

Section: Introductionmentioning

confidence: 99%

Electrically induced spin resonance fluorescence. II. Fluorescence spectra

2007

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We model the fluorescence spectra of planar spin oscillators to find conditions that maximize spin resonance fluorescence. Spin oscillators perform Rabi oscillations under the effect of a periodic effective magnetic field caused by the winding motion of an electron in a gradient of magnetic field. We show that, despite the weak coupling of the spin magnetic dipole to the vacuum, spin oscillators excited by a direct current output a few nanowatts of microwave power, which is comparable to the best microwave sources. The large quantum efficiency relies on the combination of two effects. On the one hand, the spontaneous emission rate is enhanced by the synchronization of spin oscillators, which interact through the microwave field that they emit. On the other hand, the huge Rabi frequencies experienced by spin oscillators promote spins into upper levels of Zeeman transitions, from which a radiative cascade is triggered. We demonstrate different regimes of fluorescence which correspond to different values of the Rabi period relative to the spontaneous decay time and to the oscillator dwell time in the gradient of magnetic field. We investigate the device parameters which make these regimes experimentally accessible and find conditions that optimize microwave output. We find that microwave emission is centered around the cutoff frequency of spin oscillators. This has the advantage that the peak emission frequency may be tuned from zero continuously up to a few hundred gigahertz using an electrostatic gate. Quite remarkably for a spintronics effect, electrically induced spin resonance fluorescence does not require the injection of a spin polarized current. In fact, we show that microwave spectra are mostly independent of the incoming spin polarization except for magnetic waveguides which are shorter than a certain critical length, which we will specify.

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Superradiant Spin-Flip Radiative Emission of a Spin-Polarized Free-Electron Beam

Cited by 9 publications

References 17 publications

Loss of spin entanglement for accelerated electrons in electric and magnetic fields

Loss of spin entanglement for accelerated electrons in electric and magnetic fields

Polarization radiation of vortex electrons with large orbital angular momentum

Electrically induced spin resonance fluorescence. II. Fluorescence spectra

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