Noise Suppression Using Symmetric Exchange Gates in Spin Qubits

Martins, Frederico Rodrigues; Malinowski, Filip K.; Nissen, Peter D.; Barnes, Edwin; Fallahi, Saeed; Gardner, Geoffrey C.; Manfra, Michael J.; Marcus, C. M.; Kuemmeth, Ferdinand

doi:10.1103/physrevlett.116.116801

Cited by 234 publications

(322 citation statements)

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“…Coherent evolution of excitations in charge and spin can span many sites, as, contrary to what might be expected, dissipation and decoherence rates induced by electromagnetic noise can be made > 20 times smaller than the relevant coupling energies [20,22,23]. Furthermore, local control and read-out of both charge and spin degrees of freedom have become matured areas of research, given the large ongoing effort of using quantum dots as a platform for quantum information processing [17,18,19,20,21,22,23]. In particular, excellent control of small on-site energy differences [20,28] or tunnel couplings [22,23] has been shown at specific values of electron filling and tuning.…”

Section: Introductionmentioning

confidence: 88%

“…Seminal efforts are underway in the control of artificial quantum systems, that can be made to emulate the underlying Fermi-Hubbard models [5, 6, 7, 8,9,10,11]. Electrostatically confined conduction band electrons define interacting quantum coherent spin and charge degrees of freedom that allow all-electrical pure-state initialisation and readily adhere to an engineerable Fermi-Hubbard Hamiltonian [12,13,14,15,16,17,18,19,20,21,22,23]. Until now, however, the substantial electrostatic disorder inherent to solid state has made attempts at emulating Fermi-Hubbard physics on solid-state platforms few and far between [24,25].…”

Section: Introductionmentioning

confidence: 99%

“…As such, pure state initialization of highly-entangled states is possible even without the use of adiabatic initialization schemes [27]. Coherent evolution of excitations in charge and spin can span many sites, as, contrary to what might be expected, dissipation and decoherence rates induced by electromagnetic noise can be made > 20 times smaller than the relevant coupling energies [20,22,23]. Furthermore, local control and read-out of both charge and spin degrees of freedom have become matured areas of research, given the large ongoing effort of using quantum dots as a platform for quantum information processing [17,18,19,20,21,22,23].…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, local control and read-out of both charge and spin degrees of freedom have become matured areas of research, given the large ongoing effort of using quantum dots as a platform for quantum information processing [17,18,19,20,21,22,23]. In particular, excellent control of small on-site energy differences [20,28] or tunnel couplings [22,23] has been shown at specific values of electron filling and tuning. Quantum simulation experiments can leverage many of these developments, trading off some of the experimental difficulties involved in full coherent control for ease of scaling.…”

Section: Introductionmentioning

confidence: 99%

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Quantum simulation of a Fermi–Hubbard model using a semiconductor quantum dot array

Hensgens

Fujita

Janssen

et al. 2017

Nature

323

329

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Interacting fermions on a lattice can develop strong quantum correlations, which lie at the heart of the classical intractability of many exotic phases of matter [1, 2, 3, 4]. Seminal efforts are underway in the control of artificial quantum systems, that can be made to emulate the underlying Fermi-Hubbard models [5, 6, 7, 8,9,10,11]. Electrostatically confined conduction band electrons define interacting quantum coherent spin and charge degrees of freedom that allow all-electrical pure-state initialisation and readily adhere to an engineerable Fermi-Hubbard Hamiltonian [12,13,14,15,16,17,18,19,20,21,22,23]. Until now, however, the substantial electrostatic disorder inherent to solid state has made attempts at emulating Fermi-Hubbard physics on solid-state platforms few and far between [24,25]. Here, we show that for gate-defined quantum dots, this disorder can be suppressed in a controlled manner. Novel insights and a newly developed semi-automated and scalable toolbox allow us to homogeneously and independently dial in the electron filling and nearest-neighbour tunnel coupling. Bringing these ideas and tools to fruition, we realize the first detailed characterization of the collective Coulomb blockade transition [26], which is the finite-size analogue of the interaction-driven Mott metal-to-insulator transition [1]. As automation and device fabrication of semiconductor quantum dots continue to improve, the ideas presented here show how quantum dots can be used to investigate the physics of ever more complex many-body states.

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Section: Introductionmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Quantum simulation of a Fermi–Hubbard model using a semiconductor quantum dot array

Hensgens

Fujita

Janssen

et al. 2017

Nature

323

329

View full text Add to dashboard Cite

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“…Tunnel couplings and detuning parameters can be independently tuned in quantum dots [22,23], and we set them here to t A = t B and d = 0. In this case, it can be shown thatH CQ forms a decoherence-free subspace (DFS) with respect to uniform electric field fluctuations [3].…”

mentioning

confidence: 99%

Pulse sequences for suppressing leakage in single-qubit gate operations

2017

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Many realizations of solid-state qubits involve couplings to leakage states lying outside the computational subspace, posing a threat to high-fidelity quantum gate operations. Mitigating leakage errors is especially challenging when the coupling strength is unknown, e.g., when it is caused by noise. Here we show that simple pulse sequences can be used to strongly suppress leakage errors for a qubit embedded in a three-level system. As an example, we apply our scheme to the recently proposed charge quadrupole (CQ) qubit for quantum dots. These results provide a solution to a key challenge for fault-tolerant quantum computing with solid-state elements.PACS numbers: 03.67. Ac, 73.21.La, 85.35.Be Recent advances in semiconducting quantum dots make them promising candidates for universal quantum computing [1][2][3][4][5][6]. However, performing gate operations with high enough fidelity to support fault-tolerant error correction remains a key challenge [7]. Two ways that a qubit can fail to have high fidelity are (i) the qubit could decay or dephase, and (ii) quantum information could leak out of the qubit's logical subspace into other quantum states in the physical system [8][9][10][11][12]. While several recent proposals in quantum dots have focused on suppressing dephasing from environmental noise [13,14], relatively little effort has gone into suppressing leakage [12].Several approaches for reducing leakage errors have been developed for superconducting qubits, including analytic pulse shaping [1,9] and optimal quantum control [16,17]. It is also known that leakage errors are, in principle, suppressible for a system-bath model with a composite sequence of a large number of pulses [8]. However, suppressing leakage errors below the fault-tolerant threshold under experimental conditions for quantum dot qubits is challenging, because of the need to apply smoothly varying short control pulses [18] within a time much less than the coherence times of the system, and also because the qubits experience fluctuations that vary in time and strength [19]. For semiconducting systems, these constraints preclude using analytically derived pulse shapes, since these require knowing the noise strength as an input parameter [9], or quantum control strategies that rely on optimizing an unrealistically large number of control parameters [16,17].In this work, we develop a simple and experimentally feasible protocol based on composite pulses that suppresses leakage errors in a three-level quantum system where the leakage state is coupled to one of the logical states with an unknown but static coupling strength (referred to as the quasistatic noise approximation [19]). Whereas the leakage error scales quadratically with noise amplitude in conventional pulsed-gate schemes for this model, our protocol significantly improves the gate fidelities by eliminating computational errors in the logical subspace up to fourth order in the noise amplitude and leakage errors up to sixth order.In a basis comprised of two logical states and one leakage...

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Robust Generation of Logical Qubit Singlet States with Reverse Engineering and Optimal Control with Spin Qubits

et al. 2020

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A protocol is proposed to generate singlet states of three logical qubits constructed by pairs of spins. Single and multiple operations of logical qubits are studied for the construction of an effective Hamiltonian, with which robust control fields are derived with invariant-based reverse engineering and optimal control. Moreover, systematic errors are further compensated by periodic modulation for better robustness. Furthermore, resistance to random noise and decoherence of the protocol is also shown with numerical simulations. Therefore, the protocol may provide useful perspectives for the generation of logical qubit entanglement in spin systems.

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Noise Suppression Using Symmetric Exchange Gates in Spin Qubits

Cited by 234 publications

References 29 publications

Quantum simulation of a Fermi–Hubbard model using a semiconductor quantum dot array

Quantum simulation of a Fermi–Hubbard model using a semiconductor quantum dot array

Pulse sequences for suppressing leakage in single-qubit gate operations

Robust Generation of Logical Qubit Singlet States with Reverse Engineering and Optimal Control with Spin Qubits

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