Universal Quantum Computing with Spin and Valley
arXiv:1203.5041 · doi:10.1088/1367-2630/14/8/083008
Abstract
We investigate a two-electron double quantum dot with both spin and valley degrees of freedom as they occur in graphene, carbon nanotubes, or silicon, and regard the 16-dimensional space with one electron per dot as a four-qubit logic space. In the spin-only case, it is well known that the exchange coupling between the dots combined with arbitrary single-qubit operations is sufficient for universal quantum computation. The presence of the valley degeneracy in the electronic band structure alters the form of the exchange coupling and in general leads to spin-valley entanglement. Here, we show that universal quantum computation can still be performed by exchange interaction and single-qubit gates in the presence of the additional (valley) degree of freedom. We present an explicit pulse sequence for a spin-only controlled-NOT consisting of the generalized exchange coupling and single-electron spin and valley rotations. We also propose state preparations and projective measurements with the use of adiabatic transitions between states with (1,1) and (0,2) charge distributions similar to the spin-only case, but with the additional requirement of controlling the spin and the valley Zeeman energies by an external magnetic field. Finally, we demonstrate a universal two-qubit gate between a spin and a valley qubit, allowing universal gate operations on the combined spin and valley quantum register.
18 pages, 3 figures, 1 table
References in corpus (26)
- Valley filter and valley valve in graphene
- Driven coherent oscillations of a single electron spin in a quantum dot
- Spin qubits in graphene quantum dots
- Electron spin coherence exceeding seconds in high purity silicon
- Coupling of Spin and Orbital Motion of Electrons in Carbon Nanotubes
- Universal quantum control of two-electron spin quantum bits using dynamic nuclear polarization
- Valley susceptibility of an interacting two-dimensional electron system
- Aharonov-Bohm effect and broken valley-degeneracy in graphene rings
- Two-qubit Gate of Combined Single Spin Rotation and Inter-dot Spin Exchange in a Double Quantum Dot
- Bound states and magnetic field-induced valley splitting in gate-tunable graphene quantum dots
- Electron spin decoherence in isotope-enriched silicon
- Ultra-long distance interaction between spin qubits
- Spin States in Graphene Quantum Dots
- Hyperfine interaction and electron-spin decoherence in graphene and carbon nanotube quantum dots
- Universal set of quantum gates for double-dot spin qubits with fixed interdot coupling
- Valley-based noise-resistant quantum computation using Si quantum dots
- Low-temperature, in situ tunable, uniaxial stress measurements in semiconductors using a piezoelectric actuator
- Quantized conductance in an AlAs 2D electron system quantum point contact
- Disorder-mediated electron valley resonance in carbon nanotube quantum dots
- Graphene quantum dots for valley-based quantum computing: A feasibility study
- Quantum gates between capacitively coupled double quantum dot two-spin qubits
- Spin filling of valley-orbit states in a silicon quantum dot
- Lifetime enhanced transport in silicon due to spin and valley blockade
- Coherent electrical rotations of valley states in Si quantum dots using the phase of the valley-orbit coupling
- Dephasing and Hyperfine Interaction in Carbon Nanotubes Double Quantum Dots: Disordered Case
- Dephasing and Hyperfine Interaction in Carbon Nanotubes Double Quantum Dots: The Clean Limit
Cited by in corpus (50)
- Quantum transport in carbon nanotubes
- Valley-Polarized Exciton-Polaritons in a Monolayer Semiconductor
- Pseudospin-valley coupled edge states in a photonic topological insulator
- Valleytronics in merging Dirac cones: All-electric-controlled valley filter, valve and universal reversible logic gate
- Entanglement in indistinguishable particle systems
- Nanomaterials for Quantum Information Science and Engineering
- Three-electron spin qubits
- Electron-hole crossover in gate-controlled bilayer graphene quantum dots
- Multicore Quantum Computing
- Valley polarization induced second harmonic generation in graphene
- Valley dependent anisotropic spin splitting in silicon quantum dots
- Tunable valley splitting and bipolar operation in graphene quantum dots
- Dispersive readout of valley splittings in cavity-coupled silicon quantum dots
- Valley qubit in gated MoS monolayer quantum dot
- Impurity-assisted electric control of spin-valley qubits in monolayer MoS
- Quantum teleportation with identical particles
- Hybrid spin and valley quantum computing with singlet-triplet qubits
- Probing two-electron multiplets in bilayer graphene quantum dots
- Long distance coupling of resonant exchange qubits
- Spin-valley system in a gated MoS-monolayer quantum dot
- Valley Hall Effect and Non-Local Resistance in Locally Gapped Graphene
- Universal Set of Quantum Gates for Double-Dot Exchange-Only Spin Qubits with Intradot Coupling
- Spintronics with graphene quantum dots
- Valley two-qubit system in a MoS-monolayer gated double quantum dot
- Switching between relaxation hotspots and coldspots in disordered spin qubits
- Impact of valley phase and splitting on readout of silicon spin qubits
- Performances and robustness of quantum teleportation with identical particles
- Spin-Valley Qubit Dynamics In Exchange Coupled Silicon Quantum Dots
- Phonon-assisted relaxation and decoherence of singlet-triplet qubits in Si/SiGe quantum dots
- Valley current generation using biased bilayer graphene dots
- Gap states and valley-spin filtering in transition metal dichalcogenide monolayers
- Valley relaxation in graphene due to charged impurities
- Valleytronic full configuration-interaction approach: An application to the excitation spectra of Si double-dot qubits
- Extended Hubbard model describing small multi-dot arrays in bilayer graphene
- Interaction between interface and massive states in multivalley topological heterostructures
- Nanoscale magnetic resonance spectroscopy using a carbon nanotube double quantum dot
- Quantum state transfer between valley and photon qubits
- Orbital hyperfine interaction and qubit dephasing in carbon nanotube quantum dots
- Valley-dependent transport through graphene quantum dots due to proximity-induced, staggered spin-orbit couplings
- Hydrogenic Spin-Valley states of the Bromine donor in 2H-MoTe
- Effects of biaxial strain on the impurity-induced magnetism in P-doped graphene and N-doped silicene: A first principles study
- Interacting holes in a gated WSe quantum channel: valley correlations and zigzag Wigner crystal
- Nanotube Double Quantum Dot Spin Transducer for Scalable Quantum Information Processing
- Proposal for a cavity-induced measurement of the exchange coupling in quantum dots
- Theory of field-modulated spin-valley-orbital pseudospin physics
- The role of antisymmetric orbitals and electron-electron interactions on the two-particle spin and valley blockade in graphene double quantum dots
- Emergence of half-metallic ferromagnetism and valley polarization in transition metal substituted WSTe monolayer
- Electric spin and valley Hall effects
- Interplay of Pauli blockade with electron-photon coupling in quantum dots
- Topological Tenfold Classification and the Entanglement of Two Qubits