Coupled quantum dots as quantum exclusive-OR gate

We study the formation of molecular states in a two-electron quantum dot as a function of the barrier potential dividing the dot. The increasing barrier potential drives the two electron system from an artificial helium atom to an artificial hydrogen molecule. To study this strongly coupled regime, we introduce variational wavefunctions which describe accurately two electrons in a single dot, and then study their mixing induced by the barrier. The evolution of the singlet-triplet gap with the barrier potential and with an external magnetic field is analyzed.

show abstract

“…For this purpose we go back to our model Hamiltonian (1) and set V 0 > 0. Clearly, the potential of the barrier:…”

Section: Double Dot -Formation Of Molecular Statesmentioning

confidence: 99%

“…There is currently interest in developing means of isolating spins of individual electrons and coupling them in a controlled way 1,2,3,4,5,6,7,8,9 . This problem is equivalent to a formation and controlled dissociation of an artificial hydrogen molecule.…”

Section: Introductionmentioning

confidence: 99%

Two electrons in a strongly coupled double quantum dot: From an artificial helium atom to a hydrogen molecule

Dybalski

Hawrylak

2005

Phys. Rev. B

View full text Add to dashboard Cite

show abstract

“…[2][3][4][5] This is partly motivated by electron spin long coherence times 6 and availability of scalable semiconductor technology. In the simplest approach, a physical qubit is identified with the two states of an electron spin, which can be manipulated by applying local magnetic fields.…”

Section: Introductionmentioning

confidence: 99%

Quantum circuits based on coded qubits encoded in chirality of electron spin complexes in triple quantum dots

Hsieh

Hawrylak

2010

Phys. Rev. B

Self Cite

View full text Add to dashboard Cite

We present a theory of quantum circuits based on coded qubits encoded in chirality of electron spin complexes in lateral gated semiconductor triple quantum dot molecules with one-electron spin in each dot. Using microscopic Hamiltonian we show how to initialize, coherently control, and measure the quantum state of a chirality-based coded qubit using static magnetic field and voltage tuning of individual dots. The microscopic model of two interacting coded qubits is established and mapped to an Ising Hamiltonian, resulting in nonlocal double-qubit gates.

show abstract

“…[2][3][4][5] The advantages of electron-spin-based qubits are long coherence times 6 and solid-state implementation with wellestablished scalable semiconductor technology. In the electron-spin-based qubits described here electron spins are spatially localized in the plane of the GaAs/GaAlAs heterojunction using voltages applied to metallic gates at the GaAs surface.…”

Section: Introductionmentioning

confidence: 99%

Charged-impurity-induced dephasing of a voltage-controlled coded qubit based on electron spin in a triple quantum dot

et al. 2009

Self Cite

View full text Add to dashboard Cite

We discuss the effect of a charged impurity on the qubit encoded in the two low-energy states of an electrostatically defined triple quantum dot with one-electron spin in each dot. The two qubit levels are identified with the two opposite directions of the motion of a minority spin. The effect of the charged impurity on the coded qubit is mapped onto the problem of an effective spin in a random magnetic field. The effective magnetic field is related to exchange rather than Coulomb interaction which ensures stability of the coded qubit with respect to charge fluctuations.

show abstract

Coupled quantum dots as quantum exclusive-OR gate

Cited by 73 publications

References 6 publications

Two electrons in a strongly coupled double quantum dot: From an artificial helium atom to a hydrogen molecule

Two electrons in a strongly coupled double quantum dot: From an artificial helium atom to a hydrogen molecule

Quantum circuits based on coded qubits encoded in chirality of electron spin complexes in triple quantum dots

Charged-impurity-induced dephasing of a voltage-controlled coded qubit based on electron spin in a triple quantum dot

Contact Info

Product

Resources

About