Novel E-beam lithography technique for in-situ junction fabrication: the controlled undercut
Florent Lecocq,Cécile Naud,Ioan Pop,Z. H. Peng,Iulian Matei,Thierry Crozes,Thierry Fournier,Wiebke Guichard,Olivier Buisson +8 more
Reads0
Chats0
TLDR
In this article, a shadow evaporation technique for the realization of junctions and capacitors is presented, where the design by E-beam lithography of strongly asymmetric undercuts on a bilayer resist enables in-situ fabrication of junction without the use of the well-known suspended bridge.Abstract:
We present a novel shadow evaporation technique for the realization of junctions and capacitors. The design by E-beam lithography of strongly asymmetric undercuts on a bilayer resist enables in-situ fabrication of junctions and capacitors without the use of the well-known suspended bridge[1]. The absence of bridges increases the mechanical robustness of the resist mask as well as the accessible range of the junction size, from 0.01 to more than 10000 micron square. We have fabricated Al/AlOx/Al Josephson junctions, phase qubit and capacitors using a 100kV E- beam writer. Although this high voltage enables a precise control of the undercut, implementation using a conventional 20kV E-beam is also discussed. The phase qubit coherence times, extracted from spectroscopy resonance width, Rabi and Ramsey oscillations decay and energy relaxation measurements, are longer than the ones obtained in our previous samples realized by standard techniques. These results demonstrate the high quality of the junction obtained by this controlled undercut technique.read more
Citations
More filters
Journal ArticleDOI
Confining the state of light to a quantum manifold by engineered two-photon loss
Zaki Leghtas,Steven Touzard,Ioan Pop,Angela Kou,Brian Vlastakis,Andrei Petrenko,Katrina Sliwa,Anirudh Narla,Shyam Shankar,Michael Hatridge,Matthew Reagor,Luigi Frunzio,Robert Schoelkopf,Mazyar Mirrahimi,Michel Devoret +14 more
TL;DR: In this article, the state of a superconducting resonator is confined to a manifold of coherent superpositions of multiple stable steady states, and a Schrodinger cat state spontaneously squeezes out of vacuum before decaying into a classical mixture.
Journal ArticleDOI
Autonomously stabilized entanglement between two superconducting quantum bits
Shyam Shankar,Michael Hatridge,Zaki Leghtas,K. Sliwa,A. Narla,Uri Vool,Steven Girvin,Luigi Frunzio,Mazyar Mirrahimi,Michel Devoret +9 more
TL;DR: This work demonstrates the stabilization of an entangled Bell state of a quantum register of two superconducting qubits for an arbitrary time using an autonomous feedback scheme that combines continuous drives along with a specifically engineered coupling between the two-qubit register and a dissipative reservoir.
Journal ArticleDOI
Coherent suppression of electromagnetic dissipation due to superconducting quasiparticles
TL;DR: A striking suppression of dissipation, despite the presence of lossy quasiparticle excitations above the superconducting gap, provides a powerful tool for minimizing decoherence in quantum electronic systems and could be directly exploited in quantum information experiments with superconducted quantum bits.
Journal ArticleDOI
Microwave characterization of Josephson junction arrays: implementing a low loss superinductance.
TL;DR: The plasma resonances of an array of Josephson junctions in the regime E(J)>>E(C), up to the ninth harmonic are measured, infer the successful implementation of a superinductance, an electrical element with a nondissipative impedance greater than the resistance quantum at microwave frequencies.
Journal ArticleDOI
Hot Nonequilibrium Quasiparticles in Transmon Qubits.
Kyle Serniak,M. Hays,G. de Lange,G. de Lange,S. Diamond,Shyam Shankar,Luke Burkhart,Luigi Frunzio,Manuel Houzet,Michel Devoret +9 more
TL;DR: This work systematically correlates qubit relaxation and excitation with charge-parity switches in an offset-charge-sensitive transmon qubit, and finds that quasiparticle-induced excitation events are the dominant mechanism behind the residual excited-state population in the authors' samples.