Robustness of quantum gates with hybrid spin-photon qubits in superconducting resonators

Chiesa, Alessandro; Gerace, Dario; Troiani, Filippo; Amoretti, G.; Santini, P.; Carretta, S.

doi:10.1103/physreva.89.052308

Cited by 11 publications

(21 citation statements)

References 47 publications

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“…As a third example, let us call

{scriptS}_{3} = false{R_{α} (θ), normalC normalΦ (δ) false}

the universal set of quantum gates containing all single qubit rotations and the controlled phase gate

C Φ false(δ false) = (\begin{matrix} 1 & 0 & 0 & 0 \\ 0 & 1 & 0 & 0 \\ 0 & 0 & 1 & 0 \\ 0 & 0 & 0 & e^{i δ} \end{matrix})

The latter is natively implemented on superconducting platforms with state‐dependent frequency shifts, and is closely related to the Ising interaction generated by

H_{Ising} \propto σ_{z} \otimes σ_{z}

. In view of the latter property, it is not surprising that the ZZ(δ) building block can be obtained directly from a single

C Φ (δ)

just with single qubit corrections and apart from an overall phase:

An equivalent construction with two

C Φ (δ)

is the following

where rotations around

α = x, y

enable the range of negative and small angles in those real experimental setups where the achievable phases δ in a single

C Φ (δ)

gate might be limited due to hardware constraints …”

Section: Quantum Circuitsmentioning

confidence: 99%

“…For instance, ensembles of non‐interacting spins in paramagnetic materials coherently coupled to superconducting microwave resonators have been proposed as the backbone of a novel hybrid quantum technology . This hybrid architecture would exploit the long coherence times of spin ensembles and the easy manipulation of photons in tunable resonators.…”

Section: Experimental Achievements and Prospective Technologiesmentioning

confidence: 99%

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Quantum Computers as Universal Quantum Simulators: State‐of‐the‐Art and Perspectives

et al. 2019

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The past few years have witnessed the concrete and fast spreading of quantum technologies for practical computation and simulation. In particular, quantum computing platforms based on either trapped ions or superconducting qubits have become available for simulations and benchmarking, with up to few tens of qubits that can be reliably initialized, controlled, and measured. The present Review aims at giving a comprehensive outlook on the state‐of‐the‐art capabilities offered from these near‐term noisy devices as universal quantum simulators, that is, programmable quantum computers potentially able to calculate the time evolution of many physical models. First, a pedagogic overview on the basic theoretical background pertaining digital quantum simulations is given, with a focus on hardware‐dependent mapping of spin‐type Hamiltonians into the corresponding quantum circuit as a key initial step toward simulating more complex models. Then, the main experimental achievements obtained in the last decade are reviewed, focusing on the digital quantum simulation of such spin models by employing two leading quantum architectures. Their performances are compared, and future challenges are outlined, also in view of prospective hybrid technologies, towards the ultimate goal of reaching the long‐sought quantum advantage for the simulation of complex many‐body models in the physical sciences.

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“…As a third example, let us call

{scriptS}_{3} = false{R_{α} (θ), normalC normalΦ (δ) false}

the universal set of quantum gates containing all single qubit rotations and the controlled phase gate

C Φ false(δ false) = (\begin{matrix} 1 & 0 & 0 & 0 \\ 0 & 1 & 0 & 0 \\ 0 & 0 & 1 & 0 \\ 0 & 0 & 0 & e^{i δ} \end{matrix})

The latter is natively implemented on superconducting platforms with state‐dependent frequency shifts, and is closely related to the Ising interaction generated by

H_{Ising} \propto σ_{z} \otimes σ_{z}

. In view of the latter property, it is not surprising that the ZZ(δ) building block can be obtained directly from a single

C Φ (δ)

just with single qubit corrections and apart from an overall phase:

An equivalent construction with two

C Φ (δ)

is the following

where rotations around

α = x, y

enable the range of negative and small angles in those real experimental setups where the achievable phases δ in a single

C Φ (δ)

gate might be limited due to hardware constraints …”

Section: Quantum Circuitsmentioning

confidence: 99%

Section: Experimental Achievements and Prospective Technologiesmentioning

confidence: 99%

Quantum Computers as Universal Quantum Simulators: State‐of‐the‐Art and Perspectives

et al. 2019

View full text Add to dashboard Cite

show abstract

“…In this article we investigate a master-equation approach that rests on the use of Lindblad terms [9,10,11,12,13,14,15,16,17]. Although such an approach lacks memory effects [18,11] it constitutes a minimal feasible descrip-tion of a time evolution that combines coherent and incoherent parts.…”

Section: Introductionmentioning

confidence: 99%

Investigation of thermalization in giant-spin models by different Lindblad schemes

Beckmann

Schnack

2017

Journal of Magnetism and Magnetic Materials

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The theoretical understanding of time-dependence in magnetic quantum systems is of great importance in particular for cases where a unitary time evolution is accompanied by relaxation processes. A key example is given by the dynamics of single-molecule magnets where quantum tunneling of the magnetization competes with thermal relaxation over the anisotropy barrier. In this article we investigate how good a Lindblad approach describes the relaxation in giant spin models and how the result depends on the employed operator that transmits the action of the thermal bath.

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“…In the more specific scientific community which deals with magnetic molecules for quantum computing the question of intermolecular (and other unwanted) interactions is of course of utmost importance. [1][2][3][4][5][6][7] Also in low-dimensional magnetism the question arises for instance in connection with dimerization or interchain as well as interlattice interactions. [8][9][10][11][12][13][14][15][16][17][18][19][20][21] Intermolecular exchange is also carefully taken care of when designing magnetic multi-qubit devices.…”

Section: Introductionmentioning

confidence: 99%

Influence of intermolecular interactions on magnetic observables

Schnack

2016

Phys. Rev. B

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Very often it is an implied paradigm of molecular magnetism that magnetic molecules in a crystal interact so weakly that measurements of dc magnetic observables reflect ensemble properties of single molecules. But the number of cases where the assumption of virtually non-interacting molecules does not hold grows steadily. A deviation from the non-interacting case can especially clearly be seen in clusters with antiferromagnetic couplings, where steps of the low-temperature magnetization curve are smeared out with increasing intermolecular interaction. In this investigation we demonstrate with examples in one-, two, and three space dimensions how intermolecular interactions influence typical magnetic observables such as magnetization, susceptibility and specific heat.

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Robustness of quantum gates with hybrid spin-photon qubits in superconducting resonators

Cited by 11 publications

References 47 publications

Quantum Computers as Universal Quantum Simulators: State‐of‐the‐Art and Perspectives

Quantum Computers as Universal Quantum Simulators: State‐of‐the‐Art and Perspectives

Investigation of thermalization in giant-spin models by different Lindblad schemes

Influence of intermolecular interactions on magnetic observables

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