arXiv subjects

M. Borrelli

Publications and source records attributed to M. Borrelli.

3 recordsLinked to original sources

arXiv2024

Equivalence of flexible stripline and coaxial cables for superconducting qubit control and readout pulses

We report a comparative study on microwave control lines for a transmon qubit using: (i) flexible stripline transmission lines, and (ii) semi-rigid coaxial cables. During each experiment we performed repeated measurements of the energy relaxation and coherence times of a transmon qubit using one of the wiring configurations. Each measurement run spanned 70 h to 250 h of measurement time, and four separate cooldowns were performed so that each configuration could be tested twice. From these datasets we observe that changing the microwave control lines from coaxial cables to flexible stripline transmission lines does not have a measurable effect on coherence compared to thermal cycling the system, or random coherence fluctuations. Our results open up the possibility of large scale integration of qubit control lines with integrated component with planar layouts on flexible substrate.

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arXiv2018

Thermodynamic fingerprints of non-Markovianity in a system of coupled superconducting qubits

The exploitation and characterization of memory effects arising from the interaction between system and environment is a key prerequisite for quantum reservoir engineering beyond the standard Markovian limit. In this paper we investigate a prototype of non-Markovian dynamics experimentally implementable with superconducting qubits. We rigorously quantify non-Markovianity highlighting the effects of the environmental temperature on the Markovian to non-Markovian crossover. We investigate how memory effects influence, and specifically suppress, the ability to perform work on the driven qubit. We show that the average work performed on the qubit can be used as a diagnostic tool to detect the presence or absence of memory effects.

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arXiv2017

Non-equilibrium quantum thermodynamics in Coulomb crystals

We present an in-depth study of the non-equilibrium statistics of the irreversible work produced during sudden quenches in proximity to the structural linear-zigzag transition of ion Coulomb crystals in 1+1 dimensions. By employing both an analytical approach based on a harmonic expansion and numerical simulations, we show the divergence of the average irreversible work in proximity to the transition. We show that the non-analytic behaviour of the work fluctuations can be characterized in terms of the critical exponents of the quantum Ising chain. Due to the technological advancements in trapped ion experiments, our results can be readily verified.

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