Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Stopping the rot

Philip C. E. Stamp

Published Jan 1, 2008• 0 citations
OpenAlex

Abstract

Uncontrollable outside influences undermine the whole enterprise of quantum computing. Nailing down the sources of this 'decoherence' in a solid-state system is a step towards solving the problem.

Related papers

Passive blind quantum computation with heralded single-photon sources

Gen-Le Piao, Hua-Wei Yuan, Chunhui Zhang +5 more

Blind quantum computation (BQC) is one of the most promising alternatives to solve the shortage of quantum resources in the implementation of quantum computations. However, in most reported studies on decoy-state BQCs, the source intensities are actively modulated, which, unfortunately, results in side-channel leakage and undermines system security. In this paper, we present a passive decoy-state BQC scheme with a heralded single-photon source that circumvents this problem skillfully, improving system security. Moreover, simulation results show that our passive scheme can even outperform other active schemes in the generation efficiency of blind states when using state-of-the-art equipment.

Journal of the Optical Society of America B•Jun 17, 2022•1 citation

Decoherence as an Obstacle to Quantum Computing

Tarun Sanghi, Jha, RM

•Jun 1, 2005•0 citations

Interaction-induced decoherence of solid state quantum computer

Maxim Yanchenko, Leonid Evgenevich Fedichkin

Uncontrollable interaction between qubits can completely destroy coherent state of quantum computer. We study such decoherence processes by numerical simulation of quantum computer operation performer adder algorithm. A polynomial procedure of avoiding such decoherence was also simulated.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•May 28, 2004•0 citations

Untangling the challenges of quantum computing

Nature Electronics•Mar 30, 2026•0 citations

Coulomb blockade in microscopic material defects as a source of decoherence and noise in solid-state quantum circuits

R. Banerjee, L. P. Lindoy, M. Hegedus +9 more

A critical limitation of solid-state quantum devices arises from the materials from which they are fabricated: uncontrolled surfaces, interfaces, and structural imperfections introduce numerous sources of loss and decoherence. Despite extensive efforts, linking these decoherence mechanisms to their microscopic material origins -- essential for developing effective mitigation strategies -- remains an outstanding challenge that has slowed coherence improvements. Here, using scanning gate microscopy on live superconducting circuits we identify a previously unrecognised decoherence mechanism originating from Coulomb blockade and microwave-driven charge tunnelling in metallic grains. Such grains are ubiquitous in thin-film devices fabricated by standard lithography processes. By characterising multiple defects across different devices, we find such defects to be as common and as debilitating to device performance as two-level system (TLS) defects, while originating from a fundamentally different physical mechanism. Importantly, conventional characterisation techniques would misattribute this loss to other, microwave power-independent processes. Our observations thus reveal a widespread source of decoherence in superconducting circuits, challenging the prevailing paradigm that coherence lifetimes are primarily limited by TLS defects. Eliminating metallic grains during fabrication provides a clear and practical route to suppress this mechanism, offering a pathway towards improved coherence and reduced noise in microwave-based solid-state quantum devices.

quant-pharXiv:2607.15252•Jul 17, 2026•0 citations

Quantum control and coherence of interacting spins in diamond

G. de Lange

The field of quantum science and technology has generated many ideas for new revolutionary devices that exploit the quantum mechanical properties of small-scale systems. Isolated solid state spins play a large role in quantum technologies. They can be used as basic building blocks for a quantum computer or as ultra-sensitive magnetic-field probes which can detect the extremely weak magnetic field generated by a single proton. A major hurdle for realizing these applications is the loss of quantum coherence resulting from uncontrolled interactions with spins in the environment. In the experiments described in my thesis we studied spins associated with defect centers in diamond and used new strategies for mitigating decoherence involving advanced quantum control techniques and for fundamental studies of decoherence. We show that we can prolong the coherence time of a single spin associated with a Nitrogen-Vacancy (NV) defect center in diamond with dynamical decoupling techniques. Our experiments are accurately reproduced theoretically and from this theory we conclude that, with dynamically decoupling, the spin environment can in principle be made irrelevant for the decoherence of a single spin. This removes a major obstacle for using solid-state spins in quantum science and technology. Furthermore, the dynamics in the spin environment and its influence on the NV spin is thoroughly experimentally studied. By better understanding the mechanisms behind decoherence we may one day find the answer to unresolved fundamental issues in quantum physics such as the quantum measurement problem.

•Sep 26, 2012•2 citations
Blind quantum computation (BQC) is one of the most promising alternatives to solve the shortage of quantum resources in the implementation of quantum computations. However, in most reported studies on decoy-state BQCs, the source intensities are actively modulated, which, unfortunately, results in side-channel leakage and undermines system security. In this paper, we present a passive decoy-state BQC scheme with a heralded single-photon source that circumvents this problem skillfully, improving system security. Moreover, simulation results show that our passive scheme can even outperform other active schemes in the generation efficiency of blind states when using state-of-the-art equipment.
A critical limitation of solid-state quantum devices arises from the materials from which they are fabricated: uncontrolled surfaces, interfaces, and structural imperfections introduce numerous sources of loss and decoherence. Despite extensive efforts, linking these decoherence mechanisms to their microscopic material origins -- essential for developing effective mitigation strategies -- remains an outstanding challenge that has slowed coherence improvements. Here, using scanning gate microscopy on live superconducting circuits we identify a previously unrecognised decoherence mechanism originating from Coulomb blockade and microwave-driven charge tunnelling in metallic grains. Such grains are ubiquitous in thin-film devices fabricated by standard lithography processes. By characterising multiple defects across different devices, we find such defects to be as common and as debilitating to device performance as two-level system (TLS) defects, while originating from a fundamentally different physical mechanism. Importantly, conventional characterisation techniques would misattribute this loss to other, microwave power-independent processes. Our observations thus reveal a widespread source of decoherence in superconducting circuits, challenging the prevailing paradigm that coherence lifetimes are primarily limited by TLS defects. Eliminating metallic grains during fabrication provides a clear and practical route to suppress this mechanism, offering a pathway towards improved coherence and reduced noise in microwave-based solid-state quantum devices.
The field of quantum science and technology has generated many ideas for new revolutionary devices that exploit the quantum mechanical properties of small-scale systems. Isolated solid state spins play a large role in quantum technologies. They can be used as basic building blocks for a quantum computer or as ultra-sensitive magnetic-field probes which can detect the extremely weak magnetic field generated by a single proton. A major hurdle for realizing these applications is the loss of quantum coherence resulting from uncontrolled interactions with spins in the environment. In the experiments described in my thesis we studied spins associated with defect centers in diamond and used new strategies for mitigating decoherence involving advanced quantum control techniques and for fundamental studies of decoherence. We show that we can prolong the coherence time of a single spin associated with a Nitrogen-Vacancy (NV) defect center in diamond with dynamical decoupling techniques. Our experiments are accurately reproduced theoretically and from this theory we conclude that, with dynamically decoupling, the spin environment can in principle be made irrelevant for the decoherence of a single spin. This removes a major obstacle for using solid-state spins in quantum science and technology. Furthermore, the dynamics in the spin environment and its influence on the NV spin is thoroughly experimentally studied. By better understanding the mechanisms behind decoherence we may one day find the answer to unresolved fundamental issues in quantum physics such as the quantum measurement problem.