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Helped demonstrate macroscopic quantum tunnelling and quantized energy levels in electrical circuits, establishing experimental foundations for superconducting quantum devices and precision qubit measurement.
Physical Review LettersPhysical Review LettersUniversity of California, BerkeleyClarke’s contributions connect the foundations of superconducting quantum behavior to the problem of measuring a quantum device. The 1985 experiments with Michel Devoret and John Martinis demonstrated tunnelling and discrete energy levels in Josephson-junction circuits. His subsequent research includes SQUID detection and controllable coupling between superconducting qubits. These links make his work relevant to how electrical circuits can store, manipulate and reveal quantum information. The profile treats those achievements as collaborative experimental results, without equating the foundational demonstrations with today’s complete processors.
University of California, BerkeleyPhysical Review LettersPhysical Review LettersThe work behind the recognition
Work, in context- 1985
Macroscopic quantum tunnelling in a circuit
Clarke, Michel Devoret and John Martinis measured escape from the zero-voltage state of a current-biased Josephson junction. At low temperatures the escape rate became temperature independent and agreed with the quantum-tunnelling prediction. This linked a measurable circuit variable to a specifically quantum effect.
Co-author with Michel Devoret and John Martinis; tunnelling measurement was a joint experimental result.
Source-supported recordPhysical Review Letters - 1985
Discrete energy levels in a Josephson junction
In a separate paper, Martinis, Devoret and Clarke reported quantized energy levels associated with the phase difference across a Josephson junction. The observed level positions agreed with a quantum-mechanical calculation using junction parameters measured in the classical regime.
Co-author with John Martinis and Michel Devoret; energy-level measurement was a joint experimental result.
Source-supported recordPhysical Review Letters - 2006
Controlling interactions between superconducting qubits
Clarke co-authored the research paper “Solid-State Qubits with Current-Controlled Coupling.” His Berkeley profile describes the ability to control the coupling energy between two flux qubits and reverse its sign, alongside research on SQUID-based qubit readout.
Co-author of the coupling paper listed by Berkeley; the reported device result belongs to its experimental team.
Source-supported recordUniversity of California, Berkeley
Keep in perspective
The institutional profile includes historical research described in the present tense; dated contributions here follow the named papers. All 1985 results are jointly attributed to Clarke, Devoret and Martinis.
The evidence map
Both views link each contribution to its sources. Choose a contribution on the map or read them all in the list.
Macroscopic quantum tunnelling in a circuit
Measurements of Macroscopic Quantum Tunneling out of the Zero-Voltage State of a Current-Biased Josephson Junction
Supports: Joint authorship, observed escape-rate behavior and agreement with the tunnelling prediction.
Published 28 Oct 1985 · Checked 19 Sept 2026Credit & limits: Co-author with Michel Devoret and John Martinis; tunnelling measurement was a joint experimental result.
Read the full contribution| Contribution | Evidence & what it supports | Credit & limits |
|---|---|---|
| Macroscopic quantum tunnelling in a circuit1985 | Primary paperMeasurements of Macroscopic Quantum Tunneling out of the Zero-Voltage State of a Current-Biased Josephson Junction Joint authorship, observed escape-rate behavior and agreement with the tunnelling prediction. Published 28 Oct 1985 · Checked 19 Sept 2026 | Co-author with Michel Devoret and John Martinis; tunnelling measurement was a joint experimental result. |
| Discrete energy levels in a Josephson junction1985 | Primary paperEnergy-Level Quantization in the Zero-Voltage State of a Current-Biased Josephson Junction Joint authorship and observed quantized energy levels in the Josephson-junction phase variable. Published 7 Oct 1985 · Checked 19 Sept 2026 | Co-author with John Martinis and Michel Devoret; energy-level measurement was a joint experimental result. |
| Controlling interactions between superconducting qubits2006 | Institutional recordJohn Clarke Identity, emeritus title, SQUID measurement research, flux-qubit coupling and listed 2006 Science paper. Checked 19 Sept 2026 | Co-author of the coupling paper listed by Berkeley; the reported device result belongs to its experimental team. |
Follow the evidence
3 sourcesPrimary papers, institutional records and attributed announcements. Each source supports the claims linked above.
- University of California, BerkeleyInstitutional record
John Clarke
Identity, emeritus title, SQUID measurement research, flux-qubit coupling and listed 2006 Science paper.
Checked 19 Sept 2026 - Physical Review LettersPrimary paper
Measurements of Macroscopic Quantum Tunneling out of the Zero-Voltage State of a Current-Biased Josephson Junction
Joint authorship, observed escape-rate behavior and agreement with the tunnelling prediction.
Published 28 Oct 1985 · Checked 19 Sept 2026 - Physical Review LettersPrimary paper
Energy-Level Quantization in the Zero-Voltage State of a Current-Biased Josephson Junction
Joint authorship and observed quantized energy levels in the Josephson-junction phase variable.
Published 7 Oct 1985 · Checked 19 Sept 2026