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:cond-mat/0406672 · Physical Review B

Control of spin dynamics with laser pulses: Generation of entangled states of donor-bound electrons in a Cd1−xMnx Te quantum well

Jiming Bao, Andrea V. Bragas, J. K. Furdyna, Roberto D. Merlin

Published Jan 13, 2005• 20 citations
arXivHTMLPDF

Abstract

A quantum-mechanical many-particle system may exhibit nonlocal behavior in that measurements performed on one of the particles can affect a second one that is far apart. These so-called entangled states are crucial for the implementation of quantum information protocols and gates for quantum computation. Here, we use ultrafast optical pulses and coherent pump-probe techniques to create and control spin entangled states in an ensemble of up to three non-interacting electrons bound to donors in a ${\mathrm{Cd}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}$Te quantum well. Our method, relying on the exchange interaction between optically excited excitons and the paramagnetic impurities, can in principle be applied to entangle an arbitrarily large number of electrons. A microscopic theory of impulsive stimulated Raman scattering and a model for multi-spin entanglement are presented. The signature of entanglement is the observation of overtones of donor spin-flips in the differential reflectivity of the probe pulse. Results are shown for resonant excitation of localized excitons below the gap, and above the gap where the signatures of entanglement are significantly enhanced. Data is also presented on the generation of coherent excitations of antiferromagnetically coupled manganese pairs, folded acoustic phonons, exciton Zeeman beats and entanglement involving two ${\mathrm{Mn}}^{+2}$ ions.

DOI
10.1103/physrevb.71.045314

Related papers

Optical generation of many-spin entangled states in a quantum well

Roberto D. Merlin, Jiming Bao, Andrea V. Bragas +1 more

A quantum-mechanical many-particle system may exhibit non-local behavior in that measurements performed on one of the particles can affect a second one that is far apart. These so-called entangled states are crucial for the implementation of quantum information protocols and gates for quantum computation. Here, we use ultrafast optical pulses and coherent techniques to create and control spin entangled states in an ensemble of up to three non-interacting electrons bound to donors in a CdTe quantum well. Our method, relying on the exchange interaction between localized excitons and paramagnetic impurities, can in principle be applied to entangle an arbitrarily large number of spins.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•May 25, 2004•0 citations

Optically-Generated Many Spin Entanglement in a Quantum Well

Jiming Bao

A many‐particle system may exhibit non‐local behavior in that measurements performed on one of the particles can affect a second particle that is far apart. These so‐called entangled states are essential for the implementation of quantum information protocols and gates for quantum computation. Here, we use ultrafast optical pulses and coherent techniques to create spin entangled states of non‐interacting electrons bound to donors in a CdTe quantum well.

AIP conference proceedings•Jan 1, 2005•0 citations

Coherent control of bound entangled electrons in a CdMnTe quantum well

Paul Jacobs, J. K. Furdyna, Roberto D. Merlin

Abstract Ultrafast laser pulses were used to control the spin state of a pair of entangled, donor‐bound electrons in a CdMnTe quantum well. The entanglement, mediated by an optically‐excited exciton, was characterized by pumpprobe spectroscopy. The data exhibits two dominant oscillations, one at the frequency of the spin‐flip of a donor electron and the second one at twice this frequency. Their amplitudes depend linearly on the pump power. The quantum state of the two‐electron spin system can be controlled by appropriate spatial and temporal shaping of the pump pulses. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Physica status solidi. C, Conferences and critical reviews/Physica status solidi. C, Current topics in solid state physics•Jun 13, 2008•0 citations

Many-spin quantum entanglement induced by femtosecond pulses

Gregory A. Garrett, Alka Ingale, Roberto D. Merlin +5 more

Summary form only given. Femtosecond pulses were used to generate long-lived (/spl tau/>0.1 ns) quantum-entangled states involving the spins of many individual Mn/sup 2+/ ions in Cd/sub 1-x/Mn/sub x/Te. The experiments were performed on a single crystal of Cd/sub 0.98/Mn/sub 0.02/Te with a standard pump-probe setup in the Voigt reflection geometry. We used a mode-locked Ti:sapphire laser which provided /spl sim/ 95 fs pulses at a repetition rate of 85 MHz an average-power of 80 mW and focused to a 80-/spl mu/m-diameter spot. The intensity of the reflected probe pulse measures changes in the optical constants that depend on the expectation value of the total spin for the particular entangled state /spl Psi/ created by the pump. The signature for an entanglement between states |j) and |l) is the observation of oscillations of frequency n/spl Omega//sub 0/ where n=(n/sub j/-n/sub l/). We notice that the highest harmonic of /spl Omega//sub 0/ provides a lower bound for the number of magnetic ions N that are entangled. The entanglement process, relying on coupling to localized excitons, holds promise for quantum-gate operations.

Quantum Electronics and Laser Science Conference•Jan 20, 2003•0 citations

Coherent Optical Control of a Single Donor Electron Spin

Yuxi Jiang, Amirehsan Alizadehherfati, Christine Falter +6 more

Coherent spin-photon interfaces are essential for scalable quantum networks, but their realization requires optically bright transitions, long-lived spin coherence, and complete coherent control. Donor-bound electron spins in II-VI semiconductors offer an attractive platform for optically active spin qubits because they combine strong donor-bound exciton transitions in a direct-bandgap material with a potentially nuclear-spin-free environment. However, coherent control of an individual optically active donor spin has remained elusive. Here we demonstrate optical initialization, coherent control, and readout of a single donor-bound electron spin in ZnSe. Using spin-selective donor-bound exciton optical transitions, we initialize the electron spin and directly resolve its spin-relaxation dynamics. We achieve coherent spin control with off-resonant picosecond optical pulses, as demonstrated by spin Rabi oscillations and Ramsey interference. We further coherently drive two spin-selective optical transitions and observe high-contrast coherent population trapping, demonstrating the formation of an optically controlled dark state. At higher driving strengths, multiple dark resonances reveal the hyperfine interaction between the electron and the I = 3/2 Cl nucleus. These results establish the first coherent optical control of a single donor electron spin in a II-VI semiconductor and identify isolated optical donors as a promising platform for solid-state optically active qubits.

quant-pharXiv:2610.36423•Oct 28, 2026

Optical control of electron spin coherence in CdTe/(Cd,Mg)Te quantum wells

Evgeny A. Zhukov, Dmitri R. Yakovlev, Михаил Михайлович Глазов +5 more

Optical control of the spin coherence of quantum well electrons by short laser pulses with circular or linear polarization is studied experimentally and theoretically. For that purpose the coherent electron spin dynamics in a $n$-doped CdTe/(Cd,Mg)Te quantum well structure was measured by time-resolved pump-probe Kerr rotation, using resonant excitation of the negatively charged exciton (trion) state. The amplitude and phase shifts of the electron spin beat signal in an external magnetic field, that are induced by laser control pulses, depend on the pump-control delay and polarization of the control relative to the pump pulse. Additive and nonadditive contributions to pump-induced signal due to the control are isolated experimentally. These contributions can be well described in the framework of a two-level model for the optical excitation of the resident electron to the trion.

arXiv:0912.2589•Physical Review B•Jun 16, 2010•30 citations
A quantum-mechanical many-particle system may exhibit nonlocal behavior in that measurements performed on one of the particles can affect a second one that is far apart. These so-called entangled states are crucial for the implementation of quantum information protocols and gates for quantum computation. Here, we use ultrafast optical pulses and coherent pump-probe techniques to create and control spin entangled states in an ensemble of up to three non-interacting electrons bound to donors in a Cd1\ensuremath−xMnx{\mathrm{Cd}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}Cd1\ensuremath−x​Mnx​Te quantum well. Our method, relying on the exchange interaction between optically excited excitons and the paramagnetic impurities, can in principle be applied to entangle an arbitrarily large number of electrons. A microscopic theory of impulsive stimulated Raman scattering and a model for multi-spin entanglement are presented. The signature of entanglement is the observation of overtones of donor spin-flips in the differential reflectivity of the probe pulse. Results are shown for resonant excitation of localized excitons below the gap, and above the gap where the signatures of entanglement are significantly enhanced. Data is also presented on the generation of coherent excitations of antiferromagnetically coupled manganese pairs, folded acoustic phonons, exciton Zeeman beats and entanglement involving two Mn+2{\mathrm{Mn}}^{+2}Mn+2 ions.
A quantum-mechanical many-particle system may exhibit non-local behavior in that measurements performed on one of the particles can affect a second one that is far apart. These so-called entangled states are crucial for the implementation of quantum information protocols and gates for quantum computation. Here, we use ultrafast optical pulses and coherent techniques to create and control spin entangled states in an ensemble of up to three non-interacting electrons bound to donors in a CdTe quantum well. Our method, relying on the exchange interaction between localized excitons and paramagnetic impurities, can in principle be applied to entangle an arbitrarily large number of spins.
Abstract Ultrafast laser pulses were used to control the spin state of a pair of entangled, donor‐bound electrons in a CdMnTe quantum well. The entanglement, mediated by an optically‐excited exciton, was characterized by pumpprobe spectroscopy. The data exhibits two dominant oscillations, one at the frequency of the spin‐flip of a donor electron and the second one at twice this frequency. Their amplitudes depend linearly on the pump power. The quantum state of the two‐electron spin system can be controlled by appropriate spatial and temporal shaping of the pump pulses. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Summary form only given. Femtosecond pulses were used to generate long-lived (/spl tau/>0.1 ns) quantum-entangled states involving the spins of many individual Mn/sup 2+/ ions in Cd/sub 1-x/Mn/sub x/Te. The experiments were performed on a single crystal of Cd/sub 0.98/Mn/sub 0.02/Te with a standard pump-probe setup in the Voigt reflection geometry. We used a mode-locked Ti:sapphire laser which provided /spl sim/ 95 fs pulses at a repetition rate of 85 MHz an average-power of 80 mW and focused to a 80-/spl mu/m-diameter spot. The intensity of the reflected probe pulse measures changes in the optical constants that depend on the expectation value of the total spin for the particular entangled state /spl Psi/ created by the pump. The signature for an entanglement between states |j) and |l) is the observation of oscillations of frequency n/spl Omega//sub 0/ where n=(n/sub j/-n/sub l/). We notice that the highest harmonic of /spl Omega//sub 0/ provides a lower bound for the number of magnetic ions N that are entangled. The entanglement process, relying on coupling to localized excitons, holds promise for quantum-gate operations.
Coherent spin-photon interfaces are essential for scalable quantum networks, but their realization requires optically bright transitions, long-lived spin coherence, and complete coherent control. Donor-bound electron spins in II-VI semiconductors offer an attractive platform for optically active spin qubits because they combine strong donor-bound exciton transitions in a direct-bandgap material with a potentially nuclear-spin-free environment. However, coherent control of an individual optically active donor spin has remained elusive. Here we demonstrate optical initialization, coherent control, and readout of a single donor-bound electron spin in ZnSe. Using spin-selective donor-bound exciton optical transitions, we initialize the electron spin and directly resolve its spin-relaxation dynamics. We achieve coherent spin control with off-resonant picosecond optical pulses, as demonstrated by spin Rabi oscillations and Ramsey interference. We further coherently drive two spin-selective optical transitions and observe high-contrast coherent population trapping, demonstrating the formation of an optically controlled dark state. At higher driving strengths, multiple dark resonances reveal the hyperfine interaction between the electron and the I = 3/2 Cl nucleus. These results establish the first coherent optical control of a single donor electron spin in a II-VI semiconductor and identify isolated optical donors as a promising platform for solid-state optically active qubits.
Optical control of the spin coherence of quantum well electrons by short laser pulses with circular or linear polarization is studied experimentally and theoretically. For that purpose the coherent electron spin dynamics in a nnn-doped CdTe/(Cd,Mg)Te quantum well structure was measured by time-resolved pump-probe Kerr rotation, using resonant excitation of the negatively charged exciton (trion) state. The amplitude and phase shifts of the electron spin beat signal in an external magnetic field, that are induced by laser control pulses, depend on the pump-control delay and polarization of the control relative to the pump pulse. Additive and nonadditive contributions to pump-induced signal due to the control are isolated experimentally. These contributions can be well described in the framework of a two-level model for the optical excitation of the resident electron to the trion.