Publications (16)
Energy Decay in Josephson Qubits from Non-equilibrium Quasiparticles
John M. Martinis, M. Ansmann, J. Aumentado
We calculate the energy decay rate of Josephson qubits and superconducting resonators from non-equilibrium quasiparticles. The decay rates from experiments are shown to be consiste…
Demonstration of a Tuneable Coupler for Superconducting Qubits Using Coherent, Time Domain, Two-Qubit Operations
R. C. Bialczak, M. Ansmann, M. Hofheinz +11
A major challenge in the field of quantum computing is the construction of scalable qubit coupling architectures. Here, we demonstrate a novel tuneable coupling circuit that allows…
Quantum computation of molecular geometry via many-body nuclear spin echoes
C. Zhang, R. G. Cortiñas, A. H. Karamlou +320
Quantum-information-inspired experiments in nuclear magnetic resonance spectroscopy may yield a pathway towards determining molecular structure and properties that are otherwise ch…
Stable Quantum-Correlated Many Body States through Engineered Dissipation
X. Mi, A. A. Michailidis, S. Shabani +164
Engineered dissipative reservoirs have the potential to steer many-body quantum systems toward correlated steady states useful for quantum simulation of high-temperature supercondu…
Phase transition in Random Circuit Sampling
A. Morvan, B. Villalonga, X. Mi +182
Undesired coupling to the surrounding environment destroys long-range correlations on quantum processors and hinders the coherent evolution in the nominally available computational…
High-fidelity gates in a Josephson qubit
Erik Lucero, M. Hofheinz, M. Ansmann +7
We demonstrate new experimental procedures for measuring small errors in a superconducting quantum bit (qubit). By carefully separating out gate and measurement errors, we construc…
Uncollapsing of a quantum state in a superconducting phase qubit
Nadav Katz, Matthew Neeley, M. Ansmann +8
We demonstrate in a superconducting qubit the conditional recovery ("uncollapsing") of a quantum state after a partial-collapse measurement. A weak measurement extracts information…
Transformed Dissipation in Superconducting Quantum Circuits
Matthew Neeley, M. Ansmann, Radoslaw C. Bialczak +7
Superconducting quantum circuits must be designed carefully to avoid dissipation from coupling to external control circuitry. Here we introduce the concept of current transformatio…
Decoherence Dynamics of Complex Photon States in a Superconducting Circuit
H. Wang, M. Hofheinz, M. Ansmann +9
Quantum states inevitably decay with time into a probabilistic mixture of classical states, due to their interaction with the environment and measurement instrumentation. We presen…
Measurement of the decay of Fock states in a superconducting quantum circuit
H. Wang, M. Hofheinz, M. Ansmann +8
We demonstrate the controlled generation of Fock states with up to 15 photons in a microwave coplanar waveguide resonator coupled to a superconducting phase qubit. The subsequent d…
1/f Flux Noise in Josephson Phase Qubits
Radoslaw C. Bialczak, R. McDermott, M. Ansmann +8
We present a new method to measure 1/f noise in Josephson quantum bits (qubits) that yields low-frequency spectra below 1Hz. Comparison of noise taken at positive and negative bias…
Purification-based quantum error mitigation of pair-correlated electron simulations
T. E. O'Brien, G. Anselmetti, F. Gkritsis +173
An important measure of the development of quantum computing platforms has been the simulation of increasingly complex physical systems. Prior to fault-tolerant quantum computing,…
Microwave Dielectric Loss at Single Photon Energies and milliKelvin Temperatures
Aaron D. O'Connell, M. Ansmann, R. C. Bialczak +9
The microwave performance of amorphous dielectric materials at very low temperatures and very low excitation strengths displays significant excess loss. Here, we present the loss t…
Improving the Coherence Time of Superconducting Coplanar Resonators
H. Wang, M. Hofheinz, J. Wenner +10
The quality factor and energy decay time of superconducting resonators have been measured as a function of material, geometry, and magnetic field. Once the dissipation of trapped m…
Temperature dependence of coherent oscillations in Josephson phase qubits
J. Lisenfeld, A. Lukashenko, M. Ansmann +2
We experimentally investigate the temperature dependence of Rabi oscillations and Ramsey fringes in superconducting phase qubits driven by microwave pulses. In a wide range of temp…
State tomography of capacitively shunted phase qubits with high fidelity
Matthias Steffen, M. Ansmann, R. McDermott +7
We introduce a new design concept for superconducting quantum bits (qubits) in which we explicitly separate the capacitive element from the Josephson tunnel junction for improved q…