Long-range exchange interaction between spin qubits mediated by a superconducting link at finite magnetic field

• URL: http://arxiv.org/abs/2009.05775v1
• Date: Sat, 12 Sep 2020 11:58:47 GMT
• Title: Long-range exchange interaction between spin qubits mediated by a superconducting link at finite magnetic field
• Authors: Lucia Gonzalez Rosado, Fabian Hassler, Gianluigi Catelani
• Abstract summary: We study a setup where such an extension is obtained by using a superconductor as a quantum mediator. We show that while spin non-conserving tunneling between the dots and the superconductor does not affect the exchange interaction, strong SO scattering in the superconducting bulk is detrimental.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: Solid state spin qubits are promising candidates for the realization of a quantum computer due to their long coherence times and easy electrical manipulation. However, spin-spin interactions, which are needed for entangling gates, have only limited range as they generally rely on tunneling between neighboring quantum dots. This severely constrains scalability. Proposals to extend the interaction range generally focus on coherent electron transport between dots or on extending the coupling range. Here, we study a setup where such an extension is obtained by using a superconductor as a quantum mediator. Because of its gap, the superconductor effectively acts as a long tunnel barrier. We analyze the impact of spin-orbit (SO) coupling, external magnetic fields, and the geometry of the superconductor. We show that while spin non-conserving tunneling between the dots and the superconductor due to SO coupling does not affect the exchange interaction, strong SO scattering in the superconducting bulk is detrimental. Moreover, we find that the addition of an external magnetic field decreases the strength of the exchange interaction. Fortunately, the geometry of the superconducting link offers a lot of room to optimize the interaction range, with gains of over an order of magnitude from a 2D film to a quasi-1D strip. We estimate that for superconductors with weak SO coupling (\textit{e.g.}, aluminum) exchange rates of up to 100\,MHz over a micron-scale range can be achieved with this setup in the presence of magnetic fields of the order of 100\,mT.

Related papers

• Quasiparticle effects in magnetic-field-resilient 3D transmons [0.0]
  We present measurements of the parity-switching time of a field-resilient 3D transmon with in-plane field up to 0.41T. We demonstrate that the superconducting-gap asymmetry plays a crucial role in the observed behavior. We establish that Al-AlO$_x$-Al JJs could be used in architectures for the parity-readout and manipulation of topological qubits.
  arXiv  Detail & Related papers  (2024-03-05T22:37:21Z)
• High-fidelity two-qubit gates of hybrid superconducting-semiconducting singlet-triplet qubits [0.0]
  Superconductors induce long-range interactions between the spin degrees of freedom of quantum dots. We show that this anisotropy is tunable and enables fast and high-fidelity two-qubit gates between singlet-triplet (ST) spin qubits. Our design is immune to leakage of the quantum information into noncomputational states.
  arXiv  Detail & Related papers  (2023-04-11T09:30:38Z)
• Bound state of distant photons in waveguide quantum electrodynamics [137.6408511310322]
  Quantum correlations between distant particles remain enigmatic since the birth of quantum mechanics. We predict a novel kind of bound quantum state in the simplest one-dimensional setup of two interacting particles in a box. Such states could be realized in the waveguide quantum electrodynamics platform.
  arXiv  Detail & Related papers  (2023-03-17T09:27:02Z)
• Resolving Fock states near the Kerr-free point of a superconducting resonator [51.03394077656548]
  We have designed a tunable nonlinear resonator terminated by a SNAIL (Superconducting Asymmetric Inductive eLement) We have excited photons near this Kerr-free point and characterized the device using a transmon qubit.
  arXiv  Detail & Related papers  (2022-10-18T09:55:58Z)
• Direct manipulation of a superconducting spin qubit strongly coupled to a transmon qubit [2.6810058988728342]
  Superconducting spin qubits provide a promising alternative to semiconductor qubits. We exploit a different qubit subspace using the spin-split doublet ground state of an electrostatically-defined quantum dot Josephson junction. We embed the Andreev spin qubit in a superconducting transmon qubit, demonstrating strong coherent qubit-qubit coupling.
  arXiv  Detail & Related papers  (2022-08-22T07:09:24Z)
• Coupled superconducting spin qubits with spin-orbit interaction [0.0]
  Superconducting spin qubits, also known as Andreev spin qubits, promise to combine the benefits of superconducting qubits and spin qubits defined in quantum dots. We show that superconducting spin qubits can be coupled to each other via the superconductor to implement two-qubit quantum gates. We propose a scalable network of superconducting spin qubits which is suitable for implementing the surface code.
  arXiv  Detail & Related papers  (2022-05-08T12:04:37Z)
• Superconducting coupler with exponentially large on-off ratio [68.8204255655161]
  Tunable two-qubit couplers offer an avenue to mitigate errors in multiqubit superconducting quantum processors. Most couplers operate in a narrow frequency band and target specific couplings, such as the spurious $ZZ$ interaction. We introduce a superconducting coupler that alleviates these limitations by suppressing all two-qubit interactions with an exponentially large on-off ratio.
  arXiv  Detail & Related papers  (2021-07-21T03:03:13Z)
• Electrically tuned hyperfine spectrum in neutral Tb(II)(Cp$^{\rm{iPr5}}$)$_2$ single-molecule magnet [64.10537606150362]
  Both molecular electronic and nuclear spin levels can be used as qubits. In solid state systems with dopants, an electric field was shown to effectively change the spacing between the nuclear spin qubit levels. This hyperfine Stark effect may be useful for applications of molecular nuclear spins for quantum computing.
  arXiv  Detail & Related papers  (2020-07-31T01:48:57Z)
• Waveguide Bandgap Engineering with an Array of Superconducting Qubits [101.18253437732933]
  We experimentally study a metamaterial made of eight superconducting transmon qubits with local frequency control. We observe the formation of super- and subradiant states, as well as the emergence of a polaritonic bandgap. The circuit of this work extends experiments with one and two qubits towards a full-blown quantum metamaterial.
  arXiv  Detail & Related papers  (2020-06-05T09:27:53Z)
• Optimal coupling of HoW$_{10}$ molecular magnets to superconducting circuits near spin clock transitions [85.83811987257297]
  We study the coupling of pure and magnetically diluted crystals of HoW$_10$ magnetic clusters to microwave superconducting coplanar waveguides. Results show that engineering spin-clock states of molecular systems offers a promising strategy to combine sizeable spin-photon interactions with a sufficient isolation from unwanted magnetic noise sources.
  arXiv  Detail & Related papers  (2019-11-18T11:03:06Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.