Zaki Leghtas

Professor

Center · CAS

Keywords

Awards & distinctions

2026 Winner of the 2026 Inventors' Award from Le Point magazine in the Quantum category
2019 ERC Grant

Team

CAS

Biography

Zaki Leghtas is a researcher specializing in the field of superconducting quantum circuits and the engineering of dissipative quantum systems. His work focuses on exploring nonlinear interactions between microwave photons, the autonomous stabilization of bosonic qubits, and the development of innovative methods to protect quantum information from decoherence. His research has notably led to significant advances in the manipulation of “Schrödinger’s cat” qubits, the optimization of superconducting materials such as tantalum, and the engineering of multiphoton dissipative processes for applications in fault-tolerant quantum computing. His expertise also extends to the design of high-impedance resonators, the study of Josephson harmonics in tunnel junctions, and the use of Josephson metamaterials for the dynamic control of microwave signals. His experimental and theoretical contributions aim to push the boundaries of quantum architectures by combining fundamental approaches with technological challenges.

Publication(s)

2026
Dissipating Quartets of Excitations in a Superconducting Circuit DOI : 10.1103/bjpc-8xcf
2025
High-quality superconducting tantalum resonators with beta phase defects DOI : 10.1063/5.0302324
2025
Mixing of counterpropagating signals in a traveling-wave Josephson device DOI : 10.1038/s41467-025-66190-0
2025
Dissipative Protection of a GKP Qubit in a High-Impedance Superconducting Circuit Driven by a Microwave Frequency Comb DOI : 10.1103/PhysRevX.15.011011
2025
Spectral signature of high-order photon processes enhanced by Cooper-pair pairing DOI : 10.1038/s41467-025-62047-8
2024
Correction to: Observation of Josephson harmonics in tunnel junctions (Nature Physics, (2024), 20, 5, (815-821), 10.1038/s41567-024-02400-8); [Correction to: Observation of Josephson harmonics in tunnel junctions (Nature Physics, (2024), 20, 5, (815-821), 10.1038/s41567-024-02400-8)] DOI : 10.1038/s41567-024-02491-3
2024
Dynamically Enhancing Qubit-Photon Interactions with Antisqueezing DOI : 10.1103/PRXQuantum.5.020306
2024
Quantum control of a cat qubit with bit-flip times exceeding ten seconds DOI : 10.1038/s41586-024-07294-3
2024
Observation of Josephson harmonics in tunnel junctions DOI : 10.1038/s41567-024-02400-8
2024
Correction to: Quantum control of a cat qubit with bit-flip times exceeding ten seconds (Nature, (2024), 629, 8013, (778-783), 10.1038/s41586-024-07294-3) DOI : 10.1038/s41586-024-07565-z
2024
High-Sensitivity ac-Charge Detection with a MHz-Frequency Fluxonium Qubit DOI : 10.1103/PhysRevX.14.011007
2023
Inhomogeneous magnetic fields interacting with spinful states in a double quantum dot: Evidence for a staggered spin-orbit interaction DOI : 10.1103/PhysRevB.107.085152
2023
High-performance repetition cat code using fast noisy operations DOI : 10.22331/q-2023-12-06-1198
2023
One Hundred Second Bit-Flip Time in a Two-Photon Dissipative Oscillator DOI : 10.1103/PRXQuantum.4.020350
2022
Magnifying Quantum Phase Fluctuations with Cooper-Pair Pairing DOI : 10.1103/PhysRevX.12.021002
2021
Vacuum-field-induced THz transport gap in a carbon nanotube quantum dot DOI : 10.1038/s41467-021-25733-x
2021
Multiplexed Photon Number Measurement DOI : 10.1103/PhysRevX.11.031045
2021
Energy-participation quantization of Josephson circuits DOI : 10.1038/s41534-021-00461-8
2020
Theory of interactions between cavity photons induced by a mesoscopic circuit DOI : 10.1103/PhysRevB.102.155105
2020
Irreversible Qubit-Photon Coupling for the Detection of Itinerant Microwave Photons DOI : 10.1103/PhysRevX.10.021038
2020
Exponential suppression of bit-flips in a qubit encoded in an oscillator DOI : 10.1038/s41567-020-0824-x
2019
Highly coherent spin states in carbon nanotubes coupled to cavity photons DOI : 10.1038/s41534-019-0169-4
2019
Structural Instability of Driven Josephson Circuits Prevented by an Inductive Shunt DOI : 10.1103/PhysRevApplied.11.024003
2019
Escape of a Driven Quantum Josephson Circuit into Unconfined States DOI : 10.1103/PhysRevApplied.11.014030
2018
Author Correction: Dynamics of a qubit while simultaneously monitoring its relaxation and dephasing (Nature Communications (2018) DOI: 10.1038/s41467-018-04372-9) DOI : 10.1038/s41467-018-05207-3
2018
Dynamics of a qubit while simultaneously monitoring its relaxation and dephasing /639/766/1130/1064 /639/766/483/481 /639/766/483/1139 /120 /129 /147/135 /139 /142/126 /144 article DOI : 10.1038/s41467-018-04372-9
2018
Coherent Oscillations inside a Quantum Manifold Stabilized by Dissipation DOI : 10.1103/PhysRevX.8.021005
2018
Demonstration of an Effective Ultrastrong Coupling between Two Oscillators DOI : 10.1103/PhysRevLett.121.040505
2017
Exploring ultrastrong coupling effects using a josephson mixer DOI : 10.1364/QIM.2017.QT5A.4
2017
Quantum simulation of a time-dependent ultrastrong coupling between two bosonic fields in circuit quantum electrodynamics DOI : 10.1364/QIM.2017.QT6A.48
2016
Extending the lifetime of a quantum bit with error correction in superconducting circuits DOI : 10.1038/nature18949
2016
Robust concurrent remote entanglement between two superconducting qubits DOI : 10.1103/PhysRevX.6.031036
2016
Planar Multilayer Circuit Quantum Electrodynamics DOI : 10.1103/PhysRevApplied.5.044021
2016
Theory of remote entanglement via quantum-limited phase-preserving amplification DOI : 10.1103/PhysRevA.93.062310
2015
Characterizing entanglement of an artificial atom and a cavity cat state with Bell's inequality DOI : 10.1038/ncomms9970
2015
Single-Photon-Resolved Cross-Kerr Interaction for Autonomous Stabilization of Photon-Number States DOI : 10.1103/PhysRevLett.115.180501
2015
Continuous generation and stabilization of mesoscopic field superposition states in a quantum circuit DOI : 10.1103/PhysRevA.91.013810
2015
Confining the state of light to a quantum manifold by engineered two-photon loss DOI : 10.1126/science.aaa2085
2014
Tracking photon jumps with repeated quantum non-demolition parity measurements DOI : 10.1038/nature13436
2014
Dynamically protected cat-qubits: A new paradigm for universal quantum computation DOI : 10.1088/1367-2630/16/4/045014
2013
Quantum reservoir engineering and single qubit cooling DOI : 10.3182/20130904-3-FR-2041.00072
2013
Hardware-efficient autonomous quantum memory protection DOI : 10.1103/PhysRevLett.111.120501
2013
Stabilizing a Bell state of two superconducting qubits by dissipation engineering DOI : 10.1103/PhysRevA.88.023849
2013
Demonstrating a driven reset protocol for a superconducting qubit DOI : 10.1103/PhysRevLett.110.120501
2013
Observation of quantum state collapse and revival due to the single-photon Kerr effect DOI : 10.1038/nature11902
2013
Autonomously stabilized entanglement between two superconducting quantum bits DOI : 10.1038/nature12802
2013
Deterministically encoding quantum information using 100-photon Schrödinger cat states DOI : 10.1126/science.1243289
2013
Manipulating quantum pathways on the fly DOI : 10.1103/PhysRevLett.110.223601
2013
Deterministic protocol for mapping a qubit to coherent state superpositions in a cavity DOI : 10.1103/PhysRevA.87.042315
2012
Hamiltonian identification through enhanced observability utilizing quantum control DOI : 10.1109/TAC.2012.2190209
2012
Stabilization of nonclassical states of one- and two-mode radiation fields by reservoir engineering DOI : 10.1103/PhysRevA.86.012114
2012
Quantum Control experiments as a testbed for evolutionary multi-objective algorithms DOI : 10.1007/s10710-012-9164-7
2011
Adiabatic passage and ensemble control of quantum systems DOI : 10.1088/0953-4075/44/15/154017
2011
Back and forth nudging for quantum state estimation by continuous weak measurement DOI : 10.1109/acc.2011.5991108
2009
Parameter estimation of a 3-level quantum system with a single population measurement DOI : 10.1109/CDC.2009.5400060

PhD supervision

2024 Experimental realization of a CNOT gate that preserves the bias between two cat qubits. CÉLARIER Armelle
2023 Implementation of a qubit protected by Cooper pair pairing ROVERC'H Erwan
2022 Reading scheme not harmful to quantum processors based on the cat qubit BOCQUET Adrien
2020 High-order photon interactions induced by Cooper pair pairing BORGOGNONI Alvise
2019 Macroscopic bit-flip times with a two-photon dissipation oscillator. BERDOU Camille