@article{21340,
  abstract     = {Equilibrium quantum systems are often described by a gas of weakly interacting normal modes. Bringing such systems far from equilibrium, however, can drastically enhance mode-to-mode interactions. Understanding the resulting liquid is a fundamental question for quantum statistical mechanics and a practical question for engineering driven quantum devices. To tackle this question, we probe the non-equilibrium kinetics of one-dimensional plasmons in a long chain of Josephson junctions. We introduce multimode spectroscopy to controllably study the departure from equilibrium, witnessing the evolution from pairwise coupling between plasma modes at weak driving to dramatic, high-order, cascaded couplings at strong driving. Scaling to many-mode drives, we stimulate interactions between hundreds of modes, resulting in near-continuum internal dynamics. Imaging the resulting non-equilibrium plasmon populations, we then resolve the nonlocal redistribution of energy in the response to a weak perturbation—an explicit verification of the emergence of a strongly interacting, non-equilibrium liquid of plasmons.},
  author       = {Bubis, Anton and Vigliotti, Lucia and Serbyn, Maksym and Higginbotham, Andrew P},
  issn         = {2375-2548},
  journal      = {Science Advances},
  number       = {7},
  publisher    = {American Association for the Advancement of Science},
  title        = {{Non-equilibrium plasmon liquid in a Josephson junction chain}},
  doi          = {10.1126/sciadv.ady7222},
  volume       = {12},
  year         = {2026},
}

@misc{19885,
  abstract     = {This .zip file contains the data to reproduce the figures and supplementary figures of "Automated All-RF Tuning for Spin Qubit Readout and Control" by Cornelius Carlsson and Jaime Saez-Mollejo et al.},
  author       = {Saez Mollejo, Jaime},
  publisher    = {Institute of Science and Technology Austria},
  title        = {{Automated All-RF Tuning for Spin Qubit Readout and Control}},
  doi          = {10.15479/AT:ISTA:19885},
  year         = {2025},
}

@article{20594,
  abstract     = {(Scanning) transmission electron microscopy ((S)TEM) has significantly advanced materials science but faces challenges in correlating precise atomic structure information with the functional properties of devices due to its time-intensive nature. To address this, an analytical workflow is introduced for the holistic characterization, modelling, and simulation of device heterostructures. This workflow automates the experimental (S)TEM data analysis, providing an in-depth characterization of crystallographic information, 3D orientation, elemental composition, and strain distribution. It reduces a process that typically takes days for a trained human into an automatic routine solved in minutes. Utilizing a physics-guided artificial intelligence model, it generates representative descriptions of materials and samples. The workflow culminates in creating digital twins of systems limited with at least one axis of translational invariance –3D finite element and atomic models of millions of atoms–enabling simulations that provide crucial insights into device behavior in practical applications. Demonstrated with SiGe planar heterostructures for scalable spin qubits, the workflow links digital twins to theoretical properties, revealing how atomic structure impacts materials and functional properties such as spatially-resolved phononic or electronic characteristics, or (inverse) spin orbit lengths. The versatility of the workflow is demonstrated through its application to a wide array of materials systems, device configurations, and sample morphologies.},
  author       = {Botifoll, Marc and Pinto-Huguet, Ivan and Rotunno, Enzo and Galvani, Thomas and Coll, Catalina and Kavkani, Payam Habibzadeh and Spadaro, Maria Chiara and Niquet, Yann Michel and Eriksen, Martin Børstad and Martí-Sánchez, Sara and Katsaros, Georgios and Scappucci, Giordano and Krogstrup, Peter and Isella, Giovanni and Cabot, Andreu and Merino, Gonzalo and Ordejón, Pablo and Roche, Stephan and Grillo, Vincenzo and Arbiol, Jordi},
  issn         = {1521-4095},
  journal      = {Advanced Materials},
  publisher    = {Wiley},
  title        = {{Artificial intelligence-assisted workflow for transmission electron microscopy: From data analysis automation to materials knowledge unveiling}},
  doi          = {10.1002/adma.202506785},
  year         = {2025},
}

@article{20706,
  abstract     = {We experimentally realize a quantum clock by using a charge sensor to count charges tunneling through a double quantum dot (DQD). Individual tunneling events are used as the clock’s ticks. We quantify the clock’s precision while measuring the power dissipated by the DQD and, separately, the charge sensor in both direct-current and radio-frequency readout modes. This allows us to probe the thermodynamic cost of creating ticks microscopically and recording them macroscopically. Our experiment is the first to explore the interplay between the entropy produced by a microscopic clockwork and its macroscopic measurement apparatus. We show that the latter contribution not only dwarfs the former but also unlocks greatly increased precision, because the measurement record can be exploited to optimally estimate time even when the DQD is at equilibrium. Our results suggest that the entropy produced by the amplification and measurement of a clock’s ticks, which has often been ignored in the literature, is the most important and fundamental thermodynamic cost of timekeeping at the quantum scale.},
  author       = {Wadhia, Vivek and Meier, Florian and Fedele, Federico and Silva, Ralph and Nurgalieva, Nuriya and Craig, David L. and Jirovec, Daniel and Saez Mollejo, Jaime and Ballabio, Andrea and Chrastina, Daniel and Isella, Giovanni and Huber, Marcus and Mitchison, Mark T. and Erker, Paul and Ares, Natalia},
  issn         = {1079-7114},
  journal      = {Physical Review Letters},
  number       = {20},
  publisher    = {American Physical Society},
  title        = {{Entropic costs of extracting classical ticks from a quantum clock}},
  doi          = {10.1103/5rtj-djfk},
  volume       = {135},
  year         = {2025},
}

@article{20730,
  abstract     = {Radio-frequency measurements could satisfy DiVincenzo’s readout criterion in future large-scale solid-state quantum processors, as they allow for high bandwidths and frequency multiplexing. However, the scalability potential of this readout technique can only be leveraged if quantum device tuning is performed using exclusively radio-frequency measurements, that is, without resorting to current measurements. We demonstrate an algorithm that performs automatic coarse tuning of double quantum dots with only radio-frequency measurements by exploiting their bandwidth and impedance matching. The tuning was completed within a few minutes with minimal prior knowledge about the device. Our results show that it is possible to eliminate the need for transport measurements for quantum-dot tuning, paving the way for more scalable device architectures.},
  author       = {Van Straaten, Barnaby and Fedele, Federico and Vigneau, Florian and Hickie, Joseph and Jirovec, Daniel and Ballabio, Andrea and Chrastina, Daniel and Isella, Giovanni and Katsaros, Georgios and Ares, Natalia},
  issn         = {2331-7019},
  journal      = {Physical Review Applied},
  number       = {5},
  publisher    = {American Physical Society},
  title        = {{All-rf-based coarse-tuning algorithm for quantum devices using machine learning}},
  doi          = {10.1103/v11m-dbhm},
  volume       = {24},
  year         = {2025},
}

@article{20733,
  abstract     = {The conversion of thermal energy into work is usually more efficient in the slow-driving regime, where the power output is vanishingly small. Efficient work extraction for fast-driving protocols remains an outstanding challenge at the nanoscale, where fluctuations play a significant role. In this Letter, we use a quantum-dot Szilard engine to extract work from thermal fluctuations with maximum efficiency over two decades of driving speed. We design and implement a family of optimized protocols ranging from the slow- to the fast-driving regime, and we measure the engine's efficiency as well as the mean and variance of its power output in each case. These optimized protocols exhibit significant improvements in power and efficiency compared to the naive approach. Our results also show that, when optimizing for efficiency, boosting the power output of a Szilard engine inevitably comes at the cost of increased power fluctuations.},
  author       = {Aggarwal, Kushagra and Rolandi, Alberto and Yang, Yikai and Hickie, Joseph and Jirovec, Daniel and Ballabio, Andrea and Chrastina, Daniel and Isella, Giovanni and Mitchison, Mark T. and Perarnau-Llobet, Martí and Ares, Natalia},
  issn         = {2643-1564},
  journal      = {Physical Review Research},
  number       = {3},
  publisher    = {American Physical Society},
  title        = {{Rapid optimal work extraction from a quantum-dot information engine}},
  doi          = {10.1103/q3dx-kyqj},
  volume       = {7},
  year         = {2025},
}

@misc{20750,
  author       = {Van Straaten, Barnaby and Fedele, Federico and Vigneau, Florian and Hickie, Joseph and Jirovec, Daniel and Chrastina, Daniel and Isella, Giovanni and Ares, Natalia},
  publisher    = {Zenodo},
  title        = {{All rf-based tuning algorithm for quantum devices using machine learning}},
  doi          = {10.5281/ZENODO.17352653},
  year         = {2025},
}

@article{19597,
  abstract     = {Superconductor–semiconductor hybrid systems play a crucial role in realizing nanoscale quantum devices, including hybrid qubits, Majorana bound states, and Kitaev chains. For such hybrid devices, subgap states play a prominent role in their operation. In this paper, we study these subgap states via Coulomb and tunneling spectroscopy through a superconducting island defined in a semiconductor nanowire fully coated by a superconductor. We systematically explore regimes ranging from an almost decoupled island to the open configuration. In the weak-coupling regime, the experimental observations are very similar in the absence of a magnetic field and when one flux quantum pierces the superconducting shell. Conversely, in the strong-coupling regime, significant distinctions emerge between the two cases. We attribute this distinct behavior to the existence of subgap states at one flux quantum, which become observable only for sufficiently strong coupling to the leads. We support our interpretation using a simple model to describe transport through the island. Our study highlights the importance of studying a broad range of tunnel couplings for understanding the rich physics of hybrid devices.},
  author       = {Valentini, Marco and Souto, Rubén Seoane and Borovkov, Maksim and Krogstrup, Peter and Meir, Yigal and Leijnse, Martin and Danon, Jeroen and Katsaros, Georgios},
  issn         = {2643-1564},
  journal      = {Physical Review Research},
  number       = {2},
  publisher    = {American Physical Society},
  title        = {{Subgap transport in superconductor-semiconductor hybrid islands: Weak and strong coupling regimes}},
  doi          = {10.1103/PhysRevResearch.7.023022},
  volume       = {7},
  year         = {2025},
}

@article{19401,
  abstract     = {High kinetic inductance superconductors are gaining increasing interest for the realisation of qubits, amplifiers and detectors. Moreover, thanks to their high impedance, quantum buses made of such materials enable large zero-point fluctuations of the voltage, boosting the coupling rates to spin and charge qubits. However, fully exploiting the potential of disordered or granular superconductors is challenging, as their inductance and, therefore, impedance at high values are difficult to control. Here, we report a reproducible fabrication of granular aluminium resonators by developing a wireless ohmmeter, which allows in situ measurements during film deposition and, therefore, control of the kinetic inductance of granular aluminium films. Reproducible fabrication of circuits with impedances (inductances) exceeding 13 kΩ (1 nH per square) is now possible. By integrating a 7.9 kΩ resonator with a germanium double quantum dot, we demonstrate strong charge-photon coupling with a rate of gc/2π = 566 ± 2 MHz. This broadly applicable method opens the path for novel qubits and high-fidelity, long-distance two-qubit gates.},
  author       = {Janik, Marian and Roux, Kevin Etienne Robert and Borja Espinosa, Carla N and Sagi, Oliver and Baghdadi, Abdulhamid and Adletzberger, Thomas and Calcaterra, Stefano and Botifoll, Marc and Garzón Manjón, Alba and Arbiol, Jordi and Chrastina, Daniel and Isella, Giovanni and Pop, Ioan M. and Katsaros, Georgios},
  issn         = {2041-1723},
  journal      = {Nature Communications},
  publisher    = {Springer Nature},
  title        = {{Strong charge-photon coupling in planar germanium enabled by granular aluminium superinductors}},
  doi          = {10.1038/s41467-025-57252-4},
  volume       = {16},
  year         = {2025},
}

@misc{18886,
  abstract     = {Research Data for publication 'Strong charge-photon coupling in planar germanium enabled by granular aluminium superinductors'},
  author       = {Janik, Marian},
  publisher    = {Institute of Science and Technology Austria},
  title        = {{Research data for publication 'Strong charge-photon coupling in planar germanium enabled by granular aluminium superinductors'}},
  doi          = {10.15479/AT:ISTA:18886},
  year         = {2025},
}

@misc{19409,
  abstract     = {This .zip file contains the data to reproduce the figures and supplementary figures of "Exchange anisotropies in microwave-driven singlet-triplet qubits" by Jaime Saez-Mollejo et al.
},
  author       = {Saez Mollejo, Jaime},
  publisher    = {Institute of Science and Technology Austria},
  title        = {{Exchange anisotropies in microwave-driven singlet-triplet qubits}},
  doi          = {10.15479/AT:ISTA:19409},
  year         = {2025},
}

@article{20664,
  abstract     = {Conference travel contributes to the climate footprint of academic research. Here, we provide a quantitative estimate of the carbon emissions associated with conference attendance by analyzing travel data from participants of 10 international conferences in the field of magnetic resonance, namely EUROMAR, ENC and ICMRBS. We find that attending a EUROMAR conference produces, on average, more than 1 t CO2 eq.. For the analyzed conferences outside Europe, the corresponding value is about 2–3 times higher, on average, with intercontinental trips amounting to up to 5 t. We compare these conference-related emissions to other activities associated with research and show that conference travel is a substantial portion of the total climate footprint of a researcher in magnetic resonance. We explore several strategies to reduce these emissions, including the impact of selecting conference venues more strategically and the possibility of decentralized conferences. Through a detailed comparison of train versus air travel – accounting for both direct and infrastructure-related emissions – we demonstrate that train travel offers considerable carbon savings. These data may provide a basis for strategic choices of future conferences in the field and for individuals deciding on their conference attendance.},
  author       = {Kapoor, Lucky and Ruzickova, Natalia and Zivadinovic, Predrag and Leitner, Valentin and Sisak, Maria A and Mweka, Cecelia N and Dobbelaere, Jeroen A and Katsaros, Georgios and Schanda, Paul},
  issn         = {2699-0016},
  journal      = {Magnetic Resonance},
  number       = {2},
  pages        = {243--256},
  publisher    = {Copernicus Publications},
  title        = {{Quantifying the carbon footprint of conference travel: The case of NMR meetings}},
  doi          = {10.5194/mr-6-243-2025},
  volume       = {6},
  year         = {2025},
}

@article{19424,
  abstract     = {Hole spin qubits are rapidly emerging as the workhorse of semiconducting quantum processors because of their large spin-orbit interaction, enabling fast all-electric operations at low power. However, spin-orbit interaction also causes non-uniformities in devices, resulting in locally varying qubit energies and site-dependent anisotropies. While these anisotropies can be used to drive single-spins, if not properly harnessed, they can hinder the path toward large-scale quantum processors. Here, we report on microwave-driven singlet-triplet qubits in planar germanium and use them to investigate the anisotropy of two spins in a double quantum dot. We show two distinct operating regimes depending on the magnetic field direction. For in-plane fields, the two spins are largely anisotropic, and electrically tunable, which enables to measure all the available transitions; coherence times exceeding 3 $\mu$s are extracted. For out-of-plane fields, they have an isotropic response but preserve the substantial energy difference required to address the singlet-triplet qubit. Even in this field direction, where the qubit lifetime
is strongly affected by nuclear spins, we find 400 ns coherence times. Our work adds a valuable tool to investigate and harness the anisotropy of spin qubits and can be implemented in any large-scale NxN device, facilitating the path towards scalable quantum processors.},
  author       = {Saez Mollejo, Jaime and Jirovec, Daniel and Schell, Yona A and Kukucka, Josip and Calcaterra, Stefano and Chrastina, Daniel and Isella, Giovanni and Rimbach-Russ, Maximilian and Bosco, Stefano and Katsaros, Georgios},
  issn         = {2041-1723},
  journal      = {Nature Communications},
  publisher    = {Springer Nature},
  title        = {{Exchange anisotropies in microwave-driven singlet-triplet qubits}},
  doi          = {10.1038/s41467-025-58969-y},
  volume       = {16},
  year         = {2025},
}

@phdthesis{19836,
  abstract     = {Over the past century, researchers have been fascinated by the quantum nature of the
physical world, initially striving to understand its fundamental principles and consequences, and
eventually progressing toward engineering systems that can control and manipulate quantum
properties. Today, we stand at the dawn of the quantum technology era. While some quantum
technologies follow well-defined roadmaps, others are still in the exciting and uncertain early
stages of development. In the fields of quantum computing and quantum simulation, research
is being conducted across a wide variety of platforms. Each of these demonstrates control over
quantum properties but also faces challenges in scaling up to the level of a mature technology.
This thesis explores some of the fundamental properties of hole spin qubits in planar germanium.
Semiconductor spin qubits are considered strong candidates for the realization of quantum
processors, owing to their long relaxation and coherence times, as well as their compatibility
with existing semiconductor industry infrastructure. Among these, hole spin qubits in planar
germanium are particularly promising. Their advantages include a large effective mass, which
eases fabrication constraints; inherent protection from hyperfine noise; and strong spin-orbit
interaction, which enables fast and purely electrical control. However, spin-orbit coupling also
introduces site-dependent variability across qubits, particularly in the g-tensors and spin-flip
tunneling, which might cause that the quantization axes are not aligned. In this thesis, we
investigate the tilt between the quantization axes of two hole spins hosted in a double quantum
dot as a function of both the magnetic field direction and various electrostatic configurations,
demonstrating that both parameters influence this tilt. We conclude by introducing a machine-learning-assisted routine to automatically tune baseband spin qubits. This approach may prove
to be a powerful tool for characterizing spin-orbit effects and gaining deeper insight into the
physics governing spin qubit behavior.
},
  author       = {Saez Mollejo, Jaime},
  issn         = {2663-337X},
  pages        = {175},
  publisher    = {Institute of Science and Technology Austria},
  title        = {{Singlet-triplet qubits in planar Germanium : From exchange anisotropies to autonomous tuning }},
  doi          = {10.15479/AT-ISTA-19836},
  year         = {2025},
}

@article{18602,
  abstract     = {Semiconductor quantum dots (QDs) in planar germanium (Ge) heterostructures have emerged as front-runners for future hole-based quantum processors. Here, we present strong coupling between a hole charge qubit, defined in a double quantum dot (DQD) in planar Ge, and microwave photons in a high-impedance (Zr = 1.3 kΩ) resonator based on an array of superconducting quantum interference devices (SQUIDs). Our investigation reveals vacuum-Rabi splittings with coupling strengths up to g0/2π = 260 MHz, and a cooperativity of C ~ 100, dependent on DQD tuning. Furthermore, utilizing the frequency tunability of our resonator, we explore the quenched energy splitting associated with strong Coulomb correlation effects in Ge QDs. The observed enhanced coherence of the strongly correlated excited state signals the presence of distinct symmetries within related spin functions, serving as a precursor to the strong coupling between photons and spin-charge hybrid qubits in planar Ge. This work paves the way towards coherent quantum connections between remote hole qubits in planar Ge, required to scale up hole-based quantum processors.},
  author       = {De Palma, Franco and Oppliger, Fabian and Jang, Wonjin and Bosco, Stefano and Janik, Marian and Calcaterra, Stefano and Katsaros, Georgios and Isella, Giovanni and Loss, Daniel and Scarlino, Pasquale},
  issn         = {2041-1723},
  journal      = {Nature Communications},
  publisher    = {Springer Nature},
  title        = {{Strong hole-photon coupling in planar Ge for probing charge degree and strongly correlated states}},
  doi          = {10.1038/s41467-024-54520-7},
  volume       = {15},
  year         = {2024},
}

@article{18653,
  abstract     = {Charge sensing is a sensitive technique for probing quantum devices, of particular importance for spin-qubit readout. To achieve good readout sensitivities, the proximity of the charge sensor to the device to be measured is a necessity. However, this proximity also means that the operation of the device affects, in turn, the sensor tuning and ultimately the readout sensitivity. We present an approach for compensating for this crosstalk effect allowing for the gate voltages of the measured device to be swept in a 1-V × 1-V window while maintaining a sensor configuration chosen by a Bayesian optimizer. Our algorithm will hopefully be a major contribution to the suite of fully automated solutions required for the operation of large quantum device architectures.},
  author       = {Hickie, Joseph and Van Straaten, Barnaby and Fedele, Federico and Jirovec, Daniel and Ballabio, Andrea and Chrastina, Daniel and Isella, Giovanni and Katsaros, Georgios and Ares, Natalia},
  issn         = {2331-7019},
  journal      = {Physical Review Applied},
  number       = {6},
  publisher    = {American Physical Society},
  title        = {{Automated long-range compensation of an rf quantum dot sensor}},
  doi          = {10.1103/PhysRevApplied.22.064026},
  volume       = {22},
  year         = {2024},
}

@article{15018,
  abstract     = {The epitaxial growth of a strained Ge layer, which is a promising candidate for the channel material of a hole spin qubit, has been demonstrated on 300 mm Si wafers using commercially available Si0.3Ge0.7 strain relaxed buffer (SRB) layers. The assessment of the layer and the interface qualities for a buried strained Ge layer embedded in Si0.3Ge0.7 layers is reported. The XRD reciprocal space mapping confirmed that the reduction of the growth temperature enables the 2-dimensional growth of the Ge layer fully strained with respect to the Si0.3Ge0.7. Nevertheless, dislocations at the top and/or bottom interface of the Ge layer were observed by means of electron channeling contrast imaging, suggesting the importance of the careful dislocation assessment. The interface abruptness does not depend on the selection of the precursor gases, but it is strongly influenced by the growth temperature which affects the coverage of the surface H-passivation. The mobility of 2.7 × 105 cm2/Vs is promising, while the low percolation density of 3 × 1010 /cm2 measured with a Hall-bar device at 7 K illustrates the high quality of the heterostructure thanks to the high Si0.3Ge0.7 SRB quality.},
  author       = {Shimura, Yosuke and Godfrin, Clement and Hikavyy, Andriy and Li, Roy and Aguilera Servin, Juan L and Katsaros, Georgios and Favia, Paola and Han, Han and Wan, Danny and de Greve, Kristiaan and Loo, Roger},
  issn         = {1369-8001},
  journal      = {Materials Science in Semiconductor Processing},
  keywords     = {Mechanical Engineering, Mechanics of Materials, Condensed Matter Physics, General Materials Science},
  number       = {5},
  publisher    = {Elsevier},
  title        = {{Compressively strained epitaxial Ge layers for quantum computing applications}},
  doi          = {10.1016/j.mssp.2024.108231},
  volume       = {174},
  year         = {2024},
}

@article{15320,
  abstract     = {Josephson diodes are superconducting elements that show an asymmetry in the critical current depending on the direction of the current. Here, we theoretically explore how an alternating current bias can tune the response of such a diode. We show that for slow driving there is always a regime where the system can only carry zero-voltage dc current in one direction, thus effectively behaving as an ideal Josephson diode. Under fast driving, the diode efficiency is also tunable, although the ideal regime cannot be reached in this case. We also investigate the residual dissipation due to the time-dependent current bias and show that it remains small. All our conclusions are solely based on the critical current asymmetry of the junction, and are thus compatible with any Josephson diode.},
  author       = {Seoane Souto, Rubén and Leijnse, Martin and Schrade, Constantin and Valentini, Marco and Katsaros, Georgios and Danon, Jeroen},
  issn         = {2643-1564},
  journal      = {Physical Review Research},
  number       = {2},
  publisher    = {American Physical Society},
  title        = {{Tuning the Josephson diode response with an ac current}},
  doi          = {10.1103/PhysRevResearch.6.L022002},
  volume       = {6},
  year         = {2024},
}

@article{17389,
  abstract     = {The potential of Si and SiGe-based devices for the scaling of quantum circuits is tainted by device variability. Each device needs to be tuned to operation conditions and each device realisation requires a different tuning protocol. We demonstrate that it is possible to automate the tuning of a 4-gate Si FinFET, a 5-gate GeSi nanowire and a 7-gate Ge/SiGe heterostructure double quantum dot device from scratch with the same algorithm. We achieve tuning times of 30, 10, and 92 min, respectively. The algorithm also provides insight into the parameter space landscape for each of these devices, allowing for the characterization of the regions where double quantum dot regimes are found. These results show that overarching solutions for the tuning of quantum devices are enabled by machine learning.},
  author       = {Severin, B. and Lennon, D. T. and Camenzind, L. C. and Vigneau, F. and Fedele, F. and Jirovec, Daniel and Ballabio, A. and Chrastina, D. and Isella, G. and de Kruijf, M. and Carballido, M. J. and Svab, S. and Kuhlmann, A. V. and Geyer, S. and Froning, F. N. M. and Moon, H. and Osborne, M. A. and Sejdinovic, D. and Katsaros, Georgios and Zumbühl, D. M. and Briggs, G. A. D. and Ares, N.},
  issn         = {2045-2322},
  journal      = {Scientific Reports},
  publisher    = {Springer Nature},
  title        = {{Cross-architecture tuning of silicon and SiGe-based quantum devices using machine learning}},
  doi          = {10.1038/s41598-024-67787-z},
  volume       = {14},
  year         = {2024},
}

@article{14793,
  abstract     = {Superconductor/semiconductor hybrid devices have attracted increasing interest in the past years. Superconducting electronics aims to complement semiconductor technology, while hybrid architectures are at the forefront of new ideas such as topological superconductivity and protected qubits. In this work, we engineer the induced superconductivity in two-dimensional germanium hole gas by varying the distance between the quantum well and the aluminum. We demonstrate a hard superconducting gap and realize an electrically and flux tunable superconducting diode using a superconducting quantum interference device (SQUID). This allows to tune the current phase relation (CPR), to a regime where single Cooper pair tunneling is suppressed, creating a sin(2y) CPR. Shapiro experiments complement this interpretation and the microwave drive allows to create a diode with ≈ 100% efficiency. The reported results open up the path towards integration of spin qubit devices, microwave resonators and (protected) superconducting qubits on  the same silicon technology compatible platform.},
  author       = {Valentini, Marco and Sagi, Oliver and Baghumyan, Levon and de Gijsel, Thijs and Jung, Jason and Calcaterra, Stefano and Ballabio, Andrea and Aguilera Servin, Juan L and Aggarwal, Kushagra and Janik, Marian and Adletzberger, Thomas and Seoane Souto, Rubén and Leijnse, Martin and Danon, Jeroen and Schrade, Constantin and Bakkers, Erik and Chrastina, Daniel and Isella, Giovanni and Katsaros, Georgios},
  issn         = {2041-1723},
  journal      = {Nature Communications},
  publisher    = {Springer Nature},
  title        = {{Parity-conserving Cooper-pair transport and ideal superconducting diode in planar germanium}},
  doi          = {10.1038/s41467-023-44114-0},
  volume       = {15},
  year         = {2024},
}

