Strong Charge-Photon Coupling in Planar Germanium Enabled by Granular Aluminium Superinductors

• URL: http://arxiv.org/abs/2407.03079v1
• Date: Wed, 3 Jul 2024 12:53:01 GMT
• Title: Strong Charge-Photon Coupling in Planar Germanium Enabled by Granular Aluminium Superinductors
• Authors: Marián Janík, Kevin Roux, Carla Borja Espinosa, Oliver Sagi, Abdulhamid Baghdadi, Thomas Adletzberger, Stefano Calcaterra, Marc Botifoll, Alba Garzón Manjón, Jordi Arbiol, Daniel Chrastina, Giovanni Isella, Ioan M. Pop, Georgios Katsaros,
• Abstract summary: We have integrated a granular aluminium resonator with a characteristic impedance exceeding the resistance quantum. We demonstrate strong charge-photon coupling with a rate of $g_textc/2pi= (566 pm 2)$ MHz. This method opens the path for novel qubits and high-fidelity, long-distance two-qubit gates.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: High kinetic inductance superconductors are gaining increasing interest for the realisation of qubits, amplifiers and detectors. Moreover, thanks to their high impedance, quantum buses made of such materials enable large zero-point fluctuations of the voltage, boosting the coupling rates to spin and charge qubits. However, fully exploiting the potential of disordered or granular superconductors is challenging, as their inductance and, therefore, impedance at high values are difficult to control. Here we have integrated a granular aluminium resonator, having a characteristic impedance exceeding the resistance quantum, with a germanium double quantum dot and demonstrate strong charge-photon coupling with a rate of $g_\text{c}/2\pi= (566 \pm 2)$ MHz. This was achieved due to the realisation of a wireless ohmmeter, which allows \emph{in situ} measurements during film deposition and, therefore, control of the kinetic inductance of granular aluminium films. Reproducible fabrication of circuits with impedances (inductances) exceeding 13 k$\Omega$ (1 nH per square) is now possible. This broadly applicable method opens the path for novel qubits and high-fidelity, long-distance two-qubit gates.

Related papers

• Gate-tunable kinetic inductance parametric amplifier [0.0]
  We present a gate-tunable parametric amplifier that operates without Josephson junctions. This design achieves near-quantum-limited performance, featuring more than 20 dB gain and a 30 MHz gain-bandwidth product.
  arXiv  Detail & Related papers  (2023-08-14T07:54:19Z)
• Observation of the Schmid-Bulgadaev dissipative quantum phase transition [0.0]
  We show that a Josephson junction connected to a resistor must undergo a dissipation-induced quantum phase transition from superconductor to insulator. In addition to elastic scattering, incident photons can spontaneously down-convert with a frequency-independent probability.
  arXiv  Detail & Related papers  (2023-04-12T12:35:50Z)
• Cryogenic hyperabrupt strontium titanate varactors for sensitive reflectometry of quantum dots [4.891811076560795]
  Radio frequency reflectometry techniques enable high bandwidth readout of semiconductor quantum dots. Careful impedance matching of the resonant circuit is required to achieve high sensitivity, which is challenging at cryogenic temperatures. We introduce a varactor based on strontium titanate with hyperabrupt capacitance-voltage characteristic, that is, a tunability similar to the best gallium arsenide-based devices. Our results bring small, magnetic field-resilient, highly tunable varactors to mK temperatures, expanding the toolbox of cryo-radio frequency applications.
  arXiv  Detail & Related papers  (2023-03-06T07:05:54Z)
• Enhancing the Coherence of Superconducting Quantum Bits with Electric Fields [62.997667081978825]
  We show that qubit coherence can be improved by tuning defects away from the qubit resonance using an applied DC-electric field. We also discuss how local gate electrodes can be implemented in superconducting quantum processors to enable simultaneous in-situ coherence optimization of individual qubits.
  arXiv  Detail & Related papers  (2022-08-02T16:18:30Z)
• Directional Josephson traveling-wave parametric amplifier via non-Hermitian topology [58.720142291102135]
  Low-noise microwave amplification is crucial for detecting weak signals in quantum technologies and radio astronomy. Current amplifiers do not satisfy all these requirements, severely limiting the scalability of superconducting quantum devices. Here, we demonstrate the feasibility of building a near-ideal quantum amplifier using a homogeneous Josephson junction array and the non-trivial topology of its dynamics.
  arXiv  Detail & Related papers  (2022-07-27T18:07:20Z)
• First design of a superconducting qubit for the QUB-IT experiment [50.591267188664666]
  The goal of the QUB-IT project is to realize an itinerant single-photon counter exploiting Quantum Non Demolition (QND) measurements and entangled qubits. We present the design and simulation of the first superconducting device consisting of a transmon qubit coupled to a resonator using Qiskit-Metal.
  arXiv  Detail & Related papers  (2022-07-18T07:05:10Z)
• Slowing down light in a qubit metamaterial [98.00295925462214]
  superconducting circuits in the microwave domain still lack such devices. We demonstrate slowing down electromagnetic waves in a superconducting metamaterial composed of eight qubits coupled to a common waveguide. Our findings demonstrate high flexibility of superconducting circuits to realize custom band structures.
  arXiv  Detail & Related papers  (2022-02-14T20:55:10Z)
• 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)
• Dispersive measurement of a semiconductor double quantum dot via 3D integration of a high-impedance TiN resonator [0.0]
  One major challenge to scaling quantum dot spin qubits is the dense wiring requirements. We describe a method to solve this problem by spacing the qubits out using high-impedance superconducting resonators. This work paves the way for 2D quantum dot qubit arrays with cavity mediated interactions.
  arXiv  Detail & Related papers  (2020-11-17T16:39:11Z)
• Surpassing the resistance quantum with a geometric superinductor [0.0]
  Superinductors have a characteristic impedance exceeding the resistance quantum $R_textQ approx 6.45textkOmega$ which leads to a suppression of ground state charge fluctuations. We present modeling, fabrication and characterization of 104 planar aluminum coil resonators with a characteristic impedance up to 30.9 $textkOmega$ at 5.6 GHz. Geometric superinductors are free of uncontrolled tunneling events and offer high, linearity and the ability to couple magnetically.
  arXiv  Detail & Related papers  (2020-07-03T12:22:44Z)
• 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)

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.