Right-sizing fluxonium against charge noise

@article{Mizel2019RightsizingFA,
  title={Right-sizing fluxonium against charge noise},
  author={Ari Mizel and Yariv Yanay},
  journal={arXiv: Quantum Physics},
  year={2019}
}
We analyze the charge-noise induced coherence time $T_2$ of the fluxonium qubit as a function of the number of array junctions in the device, $N$. The pure dephasing rate decreases with $N$, but we find that the relaxation rate increases, so $T_2$ achieves an optimum as a function of $N$. This optimum can be much smaller than the number typically chosen in experiments, yielding a route to improved fluxonium coherence and simplified device fabrication at the same time. 

Figures from this paper

Surpassing the Resistance Quantum with a Geometric Superinductor

The superconducting circuit community has recently discovered the promising potential of superinductors. These circuit elements have a characteristic impedance exceeding the resistance quantum

Fractional Josephson effect versus fractional charge in superconducting–normal metal hybrid circuits

Fractionally charged excitations play a central role in condensed matter physics, and can be probed in different ways. If transport occurs via dissipation-less supercurrents, they manifest as a

Compact description of quantum phase slip junctions

Quantum circuit theory is a powerful and ever-evolving tool to predict the dynamics of superconducting circuits. In its language, quantum phase slips (QPSs) are famously considered to be the exact

Majorana fermions revealing the true nature of quantum phase slip junctions

Quantum circuit theory is a powerful and ever-evolving tool to predict the dynamics of superconducting circuits. In its language, quantum phase slips are famously considered to be the exact dual to

Geometric Superinductance Qubits: Controlling Phase Delocalization across a Single Josephson Junction

There are two elementary superconducting qubit types that derive directly from the quantum harmonic oscillator. In one, the inductor is replaced by a nonlinear Josephson junction to realize the

Charge quantization and detector resolution

Charge quantization, or the absence thereof, is a central theme in quantum circuit theory, with dramatic consequences for the predicted circuit dynamics. Very recently, the question of whether or not

References

SHOWING 1-10 OF 46 REFERENCES

High-Coherence Fluxonium Qubit

We report superconducting fluxonium qubits with coherence times largely limited by energy relaxation and reproducibly satisfying T2 > 100 microseconds (T2 > 300 microseconds in one device). Moreover,

1/f Flux noise in Josephson phase qubits.

A new method to measure 1/f noise in Josephson quantum bits (qubits) that yields low-frequency spectra below 1 Hz and shows the dominant noise source to be flux noise and not junction critical-current noise.

Nanowire Superinductance Fluxonium Qubit.

A crossover in the lifetime limiting mechanism from capacitive to inductive losses is found and is explained by means of a multimode theory accounting for the distributed nature of the superinductance and the effect of the circuit nonlinearity to all orders in the Josephson potential.

Charge-insensitive qubit design derived from the Cooper pair box

Short dephasing times pose one of the main challenges in realizing a quantum computer. Different approaches have been devised to cure this problem for superconducting qubits, a prime example being

Fluxonium: Single Cooper-Pair Circuit Free of Charge Offsets

A new superconducting artificial atom is realized that is totally insensitive to offset charges, yet its energy levels manifest the anharmonic structure associated with single Cooper-pair effects, a useful component for solid-state quantum computation.

Realization of a Λ System with Metastable States of a Capacitively Shunted Fluxonium.

A Λ system in a superconducting circuit, with metastable states exhibiting lifetimes up to 8 ms, is realized, realized by adding a capacitive shunt to the original circuit design.

Collective modes in the fluxonium qubit

Superconducting qubit designs vary in complexity from single- and few-junction systems, such as the transmon and flux qubits, to the many-junction fluxonium. Here, we consider the question of whether

The flux qubit revisited to enhance coherence and reproducibility

The design and fabrication of the superconducting flux qubit is revisited, achieving a planar device with broad-frequency tunability, strong anharmonicity, high reproducibility and relaxation times in excess of 40 μs at its flux-insensitive point.

Superconducting persistent-current qubit

We present the design of a superconducting qubit that has circulating currents of opposite sign as its two states. The circuit consists of three nanoscale aluminum Josephson junctions connected in a

Demonstration of Protection of a Superconducting Qubit from Energy Decay.

A multilevel fluxonium artificial atom is designed such that the qubit's transition dipole can be exponentially suppressed by flux tuning, while it continues to dispersively interact with a cavity mode by virtual transitions to the noncomputational states.