Realization of a classical counterpart of a scalable design for adiabatic quantum computation

We implement a classical counterpart of a scalable design for adiabatic quantum computation. The key element of this design is a coupler providing controllable coupling between two bistable elements (in our case superconducting rings with a single Josephson junction playing the role of a classical counterpart of superconducting flux qubits) The coupler is also a superconducting ring with a single Josephson junction that operates in the non-hysteretic mode. The flux coupling between two bistable rings can be controlled by changing the magnetic flux through the coupler. Thereby, the coupling can be tuned from ferromagnetic trough zero to to anti-ferromagnetic.Comment: 3 pages, 3 figures v2: extended discussion experimental result

Direct Josephson coupling between superconducting flux qubits

We have demonstrated strong antiferromagnetic coupling between two three-junction flux qubits based on a shared Josephson junction, and therefore not limited by the small inductances of the qubit loops. The coupling sign and magnitude were measured by coupling the system to a high-quality superconducting tank circuit. Design modifications allowing to continuously tune the coupling strength and/or make the coupling ferromagnetic are discussed.Comment: REVTeX 4, 4 pages, 5 figures; v2: completely rewritten, added finite-temperature results and proposals for ferromagnetic galvanic couplin

Sinking islands, drowned logic; climate change and community-based adaptation discourses in Solomon Islands

Global Challenges (FSW

Weak continuous monitoring of a flux qubit using coplanar waveguide resonator

We study a flux qubit in a coplanar waveguide resonator by measuring transmission through the system. In our system with the flux qubit decoupled galvanically from the resonator, the intermediate coupling regime is achieved. In this regime dispersive readout is possible with weak backaction on the qubit. The detailed theoretical analysis and simulations give a good agreement with the experimental data and allow to make the qubit characterization.Comment: 4 pages, 3 figures, to be published in Phys. Rev.

To disclose or not? Children’s tendency to disclose peer victimisation in elementary school

This study aimed to shed light on the prevalence of chronic peer victimisation among Dutch elementary school children and factors associated with (non-)disclosure of such experiences by victims. 5,961 students from 73 schools participated (51.5% male; Mage 9.96; 77.7% native Dutch). Results showed that 12.3% of all children were victimised chronically, of which 29.4% did not disclose. Multilevel logistic regressions indicated that girls, older and native Dutch children were more likely to disclose. Moreover, experiencing depressive symptoms prompts disclosing victimisation. Anxiety, high emotion regulation skills, and perceptions of cohesion in the classroom were negatively associated with disclosure. The disclosure was not related to frequency or duration of victimisation, self-perceived social acceptance, self-worth, impulse control, or perceived classroom climate. Our study reveals information on the prevalence of peer victimisation and its disclosure, based on a nationwide study conducted in 2016–2017. It gives important insights into factors associated with disclosing victimisation experiences

Four-qubit device with mixed couplings

We present the first experimental results on a device with more than two superconducting qubits. The circuit consists of four three-junction flux qubits, with simultaneous ferro- and antiferromagnetic coupling implemented using shared Josephson junctions. Its response, which is dominated by the ground state, is characterized using low-frequency impedance measurement with a superconducting tank circuit coupled to the qubits. The results are found to be in excellent agreement with the quantum-mechanical predictions.Comment: REVTeX 4, 5pp., 7 EPS figure files. N.B.: "Alec" is my first, and "Maassen van den Brink" my family name. v2: final published version, with changed title, different sample micrograph, and several clarification