Effect of an external magnetic field on the determination of E1M1 two-photon decay rates in Be-like ions

Abstract An efficient scheme is proposed to teleport an entangled state of two superconducting (SC) qubits from Alice's to Bob's lab. This type of two-level systems has recently attracted a lot of attention due to the possible tunability of the coupling strength of the qubits with each other. To achieve the purpose, we first generate the GHZ state as the necessary teleportation channel. Then, appropriate interactions are performed in two processes between two of the five qubits, each with a certain frequency modulative external magnetic field which is applied on specific one of the qubits. Next, via applying proper gates and measurements in each lab, we observe that the teleportation can be successfully performed with maximum possible values of fidelity and success probability. At last, to make the protocol close to reality, decay rates of SC qubits are also taken into account, showing that our protocol still works well, satisfactorily.

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A model of the response of GMR of metallic multilayers to external magnetic field

Materials Science-Poland ◽

10.1515/msp-2015-0099 ◽

2015 ◽

Vol 33 (4) ◽

pp. 835-840

Author(s):

J.I. Uba ◽

A.J. Ekpunobi ◽

P.I. Ekwo

Keyword(s):

Magnetic Field ◽

External Magnetic Field ◽

Giant Magnetoresistance ◽

Ion Beam ◽

Interface Roughness ◽

Total Density ◽

Metallic Multilayers ◽

Interface Quality ◽

Qualitative Measure

AbstractIt has not been possible to transform resistivity models in terms of magnetic field in order to account for variation of giant magnetoresistance (GMR) with external magnetic field, which would have led to determination of material properties. This problem is approached mathematically via variation calculus to arrive at an exponential function that fits observed GMR values. Using this model in free electron approximation, the mean Fermi vector, susceptibility and total density of states of a number of metallic multilayers are determined from their reported GMR values. Susceptibility is found to depend on interface roughness and antiferromagnetic (AF) coupling; thus, it gives qualitative measure of interface quality and AF coupling. Comparison of susceptibilities and GMRs of electrodeposited and ion beam sputtered Co/Cu structures shows that a rough interface suppresses GMR in the former but enhances it in the latter.

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Whistler emission through transition radiation by a modulated electron beam spiralling in a magnetoplasma

Journal of Plasma Physics ◽

10.1017/s0022377899008247 ◽

2000 ◽

Vol 63 (3) ◽

pp. 285-295 ◽

Cited By ~ 8

Author(s):

M. STARODUBTSEV ◽

C. KRAFFT

Keyword(s):

Magnetic Field ◽

Electron Beam ◽

External Magnetic Field ◽

Transition Radiation ◽

Physical Processes ◽

Phase Velocities ◽

Electric Dipoles ◽

Wave Emission ◽

Loop Antennas

Transition radiation from the zone of injection of a modulated electron beam spiralling into a magnetoplasma has been identified as whistler waves propagating quasiparallel to the external magnetic field. The characteristics of the radiation are similar to the emission by localized sources, such as loop antennas and electric dipoles: resonance-cone structures at low plasma densities and energy flow along the external magnetic field at higher densities, with a diverging radiation pattern and with whistler phase velocities inversely proportional to the plasma frequency. These studies should contribute to a wider understanding of the physical processes connected with the injection of charges in a magnetoplasma – either from a gun on board a spacecraft or in a plasma chamber – and thus allow the determination of appropriate radiator characteristics in order to control, to some extent, plasma perturbations and wave emission in the region of the injector.

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TWO-PHOTON DECAY RATES OF HEAVY QUARKONIA IN THE RELATIVISTIC QUARK MODEL

Modern Physics Letters A ◽

10.1142/s021773230300971x ◽

2003 ◽

Vol 18 (09) ◽

pp. 601-607 ◽

Cited By ~ 67

Author(s):

D. EBERT ◽

R. N. FAUSTOV ◽

V. O. GALKIN

Keyword(s):

Experimental Data ◽

Quark Model ◽

Relativistic Effects ◽

Decay Rates ◽

Heavy Quarkonia ◽

Radiative Corrections ◽

Relativistic Quark Model ◽

Two Photon ◽

Photon Decay ◽

Theoretical Predictions

Two-photon decay rates of pseudoscalar, scalar and tensor states of charmonium and bottomonium are calculated in the framework of the relativistic quark model. Both relativistic effects and one-loop radiative corrections are taken into account. The obtained results are compared with other theoretical predictions and available experimental data.

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