Composite arrays of superconducting microstrip line resonators

Mohebbi, Hamid Reza; Benningshof, Olaf; Taminiau, Ivar; Miao, Guo‐Xing; Cory, David G.

doi:10.1063/1.4866691

Cited by 16 publications

(24 citation statements)

References 36 publications

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“…The superconducting microwave resonator [35] are four λ/2 microstrip line resonators in parallel rows which are separated by 65 mm. The superconducting microwave resonator [35] are four λ/2 microstrip line resonators in parallel rows which are separated by 65 mm.…”

Section: Transport Characterizationsmentioning

confidence: 99%

Superconducting Resonators Based on TiN/Tapering/NbN/Tapering/TiN Heterostructures

et al. 2016

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We fabricated a type of superconducting heterostructures, TiN/tapering/NbN/tapering/TiN, on c-cut sapphire substrates by reactive magnetron sputtering. The goal is to achieve an x-band resonator that maintains a high Q in modest magnetic fields. The structure shows (111) orientation with local epitaxial correlation, as a result of stacking face-centered-cubic structures on top of hexagonal-closepacking substrates. The artificial tapering layers vary gradually from NbN into TiN and vice versa, creating a smooth transition so that no distinct interface exists. We characterized microstrip single line resonators on these heterostructures that are promising candidates for quantum information processing with hybrid nuclear-electron spins.

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Section: Transport Characterizationsmentioning

confidence: 99%

Superconducting Resonators Based on TiN/Tapering/NbN/Tapering/TiN Heterostructures

et al. 2016

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“…where α L , α R and η are constants [42,43]. Kinetic inductance leads to a reduction in the circuit resonance frequency, coupling, and quality factor with increasing power, as shown in Figure 3(a-b).…”

Section: Pacs Numbersmentioning

confidence: 99%

Controlling Quantum Devices with Nonlinear Hardware

et al. 2015

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High fidelity coherent control of quantum systems is critical to building quantum devices and quantum computers. We provide a general optimal control framework for designing control sequences that account for hardware control distortions while maintaining robustness to environmental noise. We demonstrate the utility of our algorithm by presenting examples of robust quantum gates optimized in the presence of nonlinear distortions. We show that nonlinear classical controllers do not necessarily incur additional computational cost to pulse optimization, enabling more powerful quantum devices. PACS numbers:The ability to coherently control the dynamics of quantum systems with high fidelity is a critical component of the development of modern quantum devices, including quantum computers [1], actuators [2,3], and sensors [4][5][6] that push beyond the capabilities of classical computation and metrology. In recent years, quantum computation has presented a compelling application for quantum control, as high-fidelity control is essential to implement quantum information processors that achieve fault-tolerance [7][8][9].The performance of numerically optimized quantum gates in laboratory applications strongly depends on the accuracy of the system model used to approximate the response of the experimental system to the applied control sequence. Here we develop a general framework whereby classical control hardware components are modelled explicitly, such that their effect on a quantum system can be computed and compensated for using numerical optimal control theory (OCT) [10] algorithms to optimize control sequences. Control sequences designed using OCT algorithms, such as the GRadient Ascent Pulse Engineering (GRAPE) [11] algorithm, can be made robust to a wide variety of inhomogenities, pulse errors and noise processes [12][13][14]. These methods are also easily extended [15][16][17][18] to other applications and may be integrated into other protocols [19]. Recently, it was demonstrated how a model of linear distortions of the control sequence, such as those arising from finite bandwidth of the classical control hardware, may also be integrated into OCT algorithms [20][21][22].Here, we improve and generalize those results beyond linear kernels to any operation that smoothly maps a list of control steps to a classical field seen by the quantum system. Importantly, our framework naturally allows for robustness against uncertainties and errors due to classical control hardware. We begin developing our method generally, without making assumptions about the device of interest, so that our results may be broadly applicable to a wide range of quantum devices. We briefly discuss how our theory is easily applied to any linear distortion, and then in more detail, demonstrate with numerics how nonlinearities in control hardware, such as those found in strongly-driven superconducting resonators used for pulsed electron spin resonance (PESR) [23][24][25], may be included in OCT algorithms.With this goal in mind, we briefly review th...

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“…Indeed adiabatic evolution may be used to trigger twophoton absorption-emission pumping cycles, which allow for on demand manipulation of individual photons in distributed quantum networks, as proposed in the cavity-QED realm [26,27]. Demonstrating control by a Λ configuration in last-generation AAs would extend this scenario to the microwave arena, opening the perspective of performing demanding protocols in highly integrated solid-state quantum architectures [13,14], which are usually subject to specific design constraints [28]. Examples are adiabatic holonomic quantum computation [29], information transfer and entanglement generation [24,30,31] between remote nodes, and other sophisticated control protocols [32].…”

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confidence: 99%

“…Successful implementation of Λ-STIRAP in this class of devices would be very important, since they display the largest decoherence times observed so far [4,10], and offer the perspective of fabricating highly integrated architectures [13,14], with a rich arena of applications. These AAs have a nearly harmonic spectrum [inset of Fig.4(b)], quantified by α := ω 12 − ω 01 and β := ω 23 − ω 12 for the four lowest energy levels.…”

mentioning

confidence: 99%

“…complex quantum architectures minimizing effects of decoherence [9,10]. In this scenario artificial atoms (AAs) are very promising since, compared to their natural counterparts, they allow for a larger degree of integration [11][12][13][14], on-chip tunability, stronger couplings [15] and easier production and detection of signals in the novel regime of microwave quantum photonics [16]. Decoherence due to strong coupling to the solid-state environment [6] is their major drawback.…”

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confidence: 99%

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Coherent manipulation of noise-protected superconducting artificial atoms in the Lambda scheme

et al. 2016

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We propose a new protocol for the manipulation of a three-level artificial atom in Lambda (Λ) configuration. It allows faithful, selective and robust population transfer analogous to stimulated Raman adiabatic passage (Λ-STIRAP), in last-generation superconducting artificial atoms, where protection from noise implies the absence of a direct pump coupling. It combines the use of a two-photon pump pulse with suitable advanced control, operated by a slow modulation of the phase of the external fields, leveraging on the stability of semiclassical microwave drives. This protocol is a building block for manipulation of microwave photons in complex quantum architectures. Its demonstration would be a benchmark for the implementation of a class of multilevel advanced control procedures for quantum computation and microwave quantum photonics in systems based on artificial atoms. [6][7][8]. These are currently investigated roadmaps towards the design of fault tolerant hardware, i.e. complex quantum architectures minimizing effects of decoherence [9,10]. In this scenario artificial atoms (AAs) are very promising since, compared to their natural counterparts, they allow for a larger degree of integration [11][12][13][14], on-chip tunability, stronger couplings [15] and easier production and detection of signals in the novel regime of microwave quantum photonics [16]. Decoherence due to strong coupling to the solid-state environment [6] is their major drawback. Over the years it has considerably softened [10] yielding last-generation superconducting devices with decoherence times in the range ∼ 1 − 100 µs [2, 4,20].Combining potential advantages of AAs is by no means straightforward. Protection from decoherence often implies strong constraints to available external control, which pose key challenges when larger architectures are considered [14]. In this work we study a simple and paradigmatic example, namely a three-level AA driven by a two-tone electric field in the Lambda (Λ) configuration [ Fig.1(a)]. Implementation of this control scheme in lastgeneration superconducting hardware may in principle benefit from low decoherence, which however is achieved at the expenses of suppressing the direct coupling of the pump field, and of possible limitations of selectivity in addressing specific transitions. In this work we show how to implement an efficient Λ configuration in these conditions, and we propose a dynamical scheme allowing to operate quantum control. This solves the problem raised in the last decade by several theoretical proposals on the implementation of advanced control by a Λ-scheme in AAs [3,[21][22][23][24][25], which still awaits experimental demonstration.Quantum control via a dynamical Λ scheme is very important because it may provide a fundamental building block for processing in complex architectures. Indeed adiabatic evolution may be used to trigger twophoton absorption-emission pumping cycles, which allow for on demand manipulation of individual photons in distributed quantum networks, as proposed in the ...

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Composite arrays of superconducting microstrip line resonators

Cited by 16 publications

References 36 publications

Superconducting Resonators Based on TiN/Tapering/NbN/Tapering/TiN Heterostructures

Superconducting Resonators Based on TiN/Tapering/NbN/Tapering/TiN Heterostructures

Controlling Quantum Devices with Nonlinear Hardware

Coherent manipulation of noise-protected superconducting artificial atoms in the Lambda scheme

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