Christopher Gies
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Connection between Memory Performance and Optical Absorption in Quantum Reservoir Computing Open
Quantum reservoir computing (QRC) offers a promising paradigm for harnessing quantum systems for machine learning tasks, especially in the era of noisy intermediate-scale quantum devices. While information-theoretical benchmarks like short…
QCSE: A Pretrained Quantum Context-Sensitive Word Embedding for Natural Language Processing Open
Quantum Natural Language Processing (QNLP) offers a novel approach to encoding and understanding the complexity of natural languages through the power of quantum computation. This paper presents a pretrained quantum context-sensitive embed…
View article: Enhancement of Indistinguishable Photon Emission from a GaAs Quantum Dot via Charge Noise Suppression
Enhancement of Indistinguishable Photon Emission from a GaAs Quantum Dot via Charge Noise Suppression Open
The generation of indistinguishable single photons is a fundamental requirement for future quantum technologies, particularly in quantum repeater networks and for distributed quantum computing based on entanglement distribution. However, s…
Harnessing Photon Indistinguishability in Quantum Extreme Learning Machines Open
This study investigates Quantum Extreme Learning Machines (QELMs), which enhance classical Extreme Learning Machines (ELMs) by incorporating quantum features.
Harnessing Photon Indistinguishability in Quantum Extreme Learning Machines Open
Recent advancements in machine learning have led to an exponential increase in computational demands, driving the need for innovative computing platforms. Quantum computing, with its Hilbert space scaling exponentially with the number of p…
Expressivity Limits of Quantum Reservoir Computing Open
We investigate the fundamental expressivity limits of quantum reservoir computing (QRC) by establishing a formal connection to parametrized quantum circuit quantum machine learning (PQC-QML). We analytically prove, and numerically corrobor…
Connection between memory performance and optical absorption in quantum reservoir computing Open
The fading memory property is a key requirement for reservoir computers -- a specific type of recurrent neural network with fixed internal weights. While mostly undesired in gate-based quantum computing, dissipation due to material imperfe…
Impact of phonon lifetimes on the single-photon indistinguishability in quantum emitters based on 2D materials Open
Localized excitons in two-dimensional (2D) materials are considered as promising sources of single photons on demand. The photon indistinguishability as key figure of merit for quantum information processing is strongly influenced by the c…
Gate‐Based Protocol Simulations for Quantum Repeaters using Quantum‐Dot Molecules in Switchable Electric Fields Open
Electrically controllable quantum‐dot molecules (QDMs) are a promising platform for deterministic entanglement generation and, as such, a resource for quantum‐repeater networks. A microscopic open‐quantum‐systems approach based on a time‐d…
Gate-based protocol simulations for quantum repeaters using quantum-dot molecules in switchable electric fields Open
Electrically controllable quantum-dot molecules (QDMs) are a promising platform for deterministic entanglement generation and, as such, a resource for quantum-repeater networks. We develop a microscopic open-quantum-systems approach based …
Engineering the impact of phonon dephasing on the coherence of a WSe$_{2}$ single-photon source via cavity quantum electrodynamics Open
Emitter dephasing is one of the key issues in the performance of solid-state single photon sources. Among the various sources of dephasing, acoustic phonons play a central role in adding decoherence to the single photon emission. Here, we …
In-situ spontaneous emission control of MoSe$_2$-WSe$_2$ interlayer excitons with near-unity quantum yield Open
Optical resonators are a powerful platform to control the spontaneous emission dynamics of excitons in solid-state nanostructures. Here, we study a MoSe$_2$-WSe$_2$ van-der-Waals heterostructure that is integrated in a widely tunable open …
Confined-state physics and signs of fermionization of moiré excitons in WSe<sub>2</sub>/MoSe<sub>2</sub> heterobilayers Open
We revisit and extend the standard bosonic interpretation of interlayer excitons (ILX) in the moiré potential of twisted heterostructures of transition-metal dichalcogenides. In our experiments, we probe a high quality MoSe 2 /WSe 2 van de…
Signatures of superradiance as a witness to multipartite entanglement Open
Generation and detection of entanglement is at the forefront of most quantum information technologies. There is a plethora of techniques that reveal entanglement on the basis of only partial information about the underlying quantum state, …
Confined-state physics and signs of fermionization of moiré excitons in WSe$_2$/MoSe$_2$ heterobilayers Open
We revisit and extend the standard bosonic interpretation of interlayer excitons in the moiré potential of twisted heterostructures of transition-metal dichalcogenides. In our experiments, we probe a high quality MoSe$_2$/WSe$_2$ van der W…
Exploring quantum mechanical advantage for reservoir computing Open
Quantum reservoir computing is an emerging field in machine learning with quantum systems. While classical reservoir computing has proven to be a capable concept of enabling machine learning on real, complex dynamical systems with many deg…
Exploring the effect of dielectric screening on neutral and charged-exciton properties in monolayer and bilayer MoTe2 Open
Dielectric engineering of heterostructures made from two-dimensional van der Waals semiconductors is a unique and powerful tool to tailor the electric and optical band gaps solely via the dielectric environment and the crystal thickness mo…
Multipartite entanglement generation in coupled microcavity arrays Open
We consider photonic arrays made from quantum emitters in optically coupled microcavities as a platform for entanglement generation. These offer a large degree of tunability with the possibility of site-selective optical excitation. Cohere…
Quantum Fluctuations and Lineshape Anomaly in a High‐<i>β</i> Silver‐Coated InP‐Based Metallic Nanolaser Open
Metallic nanocavity lasers provide important technological advancement toward even smaller integrable light sources. They give access to widely unexplored lasing physics in which the distinction between different operational regimes, like …
Intrinsic circularly polarized exciton emission in a twisted van der Waals heterostructure Open
The investigation of excitons in van-der-Waals heterostructures has led to profound insights into the interplay of crystal symmetries and fundamental effects of light-matter coupling. In particular, the polarization selection rules in undi…
Revisiting the Siegert relation for the partially coherent regime of nanolasers Open
The Siegert relation connects the first- and second-order coherence properties of light. Although strictly valid only in the thermal regime and in the absence of correlations, this relation is routinely extended to the partially coherent r…
Moiré-Bose-Hubbard model for interlayer excitons in twisted transition metal dichalcogenide heterostructures Open
In bilayers of semiconducting transition metal dichalcogenides, the twist\nangle between layers can be used to introduce a highly regular periodic\npotential modulation on a length scale that is large compared to the unit cell.\nIn such st…
Atomically Thin van der Waals Semiconductors—A Theoretical Perspective Open
2D semiconductors and their heterostructures have developed into a flourishing research field. A more or less simultaneous start of experimental and theoretical developments has led to continuous advancements in both branches of physics th…
View article: Data repository for "Observation of two-dimensional Anderson Localisation of Ultracold Atoms", Nature Communications 11, 4942 (2020)
Data repository for "Observation of two-dimensional Anderson Localisation of Ultracold Atoms", Nature Communications 11, 4942 (2020) Open
This is the full dataset for the main manuscript and supplementary material of "Observation of two-dimensional Anderson Localisation of Ultracold Atoms"
View article: Data repository for "Observation of two-dimensional Anderson Localisation of Ultracold Atoms", Nature Communications 11, 4942 (2020)
Data repository for "Observation of two-dimensional Anderson Localisation of Ultracold Atoms", Nature Communications 11, 4942 (2020) Open
This is the full dataset for the main manuscript and supplementary material of
Thresholdless Transition to Coherent Emission at Telecom Wavelengths from Coaxial Nanolasers with Excitation Power Dependent β‐Factors Open
The ongoing miniaturization of semiconductor lasers has enabled ultra‐low threshold devices and even provided a path to approach thresholdless lasing with linear input–output characteristics. Such nanoscale lasers have initiated a discours…
View article: Observation of two-dimensional Anderson localisation of ultracold atoms
Observation of two-dimensional Anderson localisation of ultracold atoms Open
Anderson localisation -- the inhibition of wave propagation in disordered media -- is a surprising interference phenomenon which is particularly intriguing in two-dimensional (2D) systems. While an ideal, non-interacting 2D system of infin…
Polariton hyperspectral imaging of two-dimensional semiconductor crystals Open
Atomically thin crystals of transition metal dichalcogenides (TMDs) host excitons with strong binding energies and sizable light-matter interactions. Coupled to optical cavities, monolayer TMDs routinely reach the regime of strong light-ma…
Prospects and Limitations of Transition Metal Dichalcogenide Laser Gain Materials Open
Nanolasers operate with a minimal amount of active material and low losses. In this regime, single layers of transition-metal dichalcogenides (TMDs) are being investigated as next generation gain materials due to their high quantum efficie…
Delayed Transition to Coherent Emission in Nanolasers with Extended Gain Media Open
The realization of high-$\\beta$ lasers is one of the prime applications of\ncavity-QED promising ultra-low thresholds, integrability and reduced power\nconsumption in the field of \\textit{green photonics}. In such nanolasers\nspontaneous…