UvA-DARE (

UvA-DARE (

Reverse engineering of single-qubit quantum gates

In this work, we address the problem of designing single-qubit quantum gates by means of a linearly-polarized field. We show that any desired one-qubit gate corresponding to a special unitary matrix can be generated by a modulated sinusoidal field. The only approximation involved is the rotating-wave-approximation. The...

Contextuality in the $n$-qubit Pauli group

The $n$-qubit Pauli group is an essential ingredient to most quantum applications, from computing and error correction to benchmarking and simulation. Despite comprising merely a discrete set of operators, it exhibits many quintessential features of quantum theory, including contextuality, which has been identified as...

Experimental benchmark of pseudo-Hermitian qubit sensing via Naimark dilation

Non-Hermitian dynamics can sharply amplify the response of a quantum sensor near eigenstate coalescence, but whether this amplification yields a genuine metrological gain depends on how the non-unitary evolution is physically realised and how its resources are counted. We address this question experimentally by imp...

Optimizing LZSM protocol for high-fidelity gates in open-system fluxonium

Quantum gates based on resonant Rabi oscillations are inherently slow for small-frequency qubits. They are also prone to errors due to counter-rotating terms. However, when the anharmonicity is sufficiently high, as in the fluxonium architecture, alternative manipulation protocols can outperform standard resonant drivi...

Ultrafast quantum gate operations in a Kramers-Henneberger atom Qubit

We propose and demonstrate the Kramers-Henneberger KH) atom as a novel qubit platform for ultrafast single-qubit gate operations. In the KH frame, the time-averaged strong laser field engineers a double-well potential whose two lowest eigenstates define the qubit basis, so that the computational structure is created an...