arXiv subjects

Matthias Heinrich

Publications and source records attributed to Matthias Heinrich.

At least 19 recordsLinked to original sources

arXiv2026

Emergence of Propagating Exciton-Polaritons in Hybrid Waveguide-van der Waals Heterostructures

Integrating few-layer materials into photonic circuits is a promising concept for novel on-chip photonic applications. We incorporate transition metal dichalcogenides (TMDs) with femtosecond-laser-written surface waveguides, which are embedded in fused silica chips. Our novel low-temperature optical spectroscopy setup enables coupling to the waveguide and simultaneous focus from the top to the TMD layer for a distinct excitation and collection of micro-photoluminescence ($\mu$PL) signals in several measurement geometries. Along these lines, we observe spectral changes of the A exciton for encapsulated TMD monolayers when capturing the $\mu$PL signal propagating through the waveguide. Depending on the thickness of the encapsulation with hexagonal boron nitride (hBN), these changes manifest as energetic redshifts of the A exciton, or even a splitting of the A exciton into two components. We attribute this behavior to strong coupling of the waveguide mode and the exciton in the sample, giving rise to the formation of propagating exciton-polaritons. Our interpretation is supported by calculations for a simplified model of a slab waveguide in the vicinity of an exciton by using the transfer matrix method. Having proven to be a highly adaptable framework for the study of propagating polaritons, our experimental platform likewise holds great promise for harnessing the unique properties of exciton-polaristons in integrated photonic circuits.

cond-mat.mes-hall↗

arXiv2026

Experimental observation of hyperbolic spacetime dynamics

Understanding quantum dynamics in curved spacetime is a central challenge at the intersection of quantum mechanics and gravity. Anti-de-Sitter (AdS) spacetime plays a pivotal role in the context of the AdS/CFT correspondence, which relates gravitational dynamics in the AdS bulk to a conformal field theory (CFT) living on its boundary. Despite its foundational importance, direct experimental access to dynamical quantum phenomena in Lorentzian AdS spacetime has so far remained out of reach. Here, we report the first experimental emulation of fermionic wave packet dynamics in Lorentzian AdS spacetime using a photonic platform. By mapping the Dirac equation in curved spacetime onto the propagation of light in engineered wave\-guide arrays, we directly observe gravitational confinement of relativistic wave packets and resolve their center-of-mass motion in real time. We identify a characteristic superposition of slow geodesic oscillations governed solely by spacetime curvature and fast Zitterbewegung arising from relativistic particle--antiparticle interference. While the geodesic frequency is independent of fermion mass, the Zitterbewegung frequency exhibits a distinct joint dependence on mass and curvature, revealing a curvature-induced modification of relativistic quantum dynamics. Our results provide the first quantitative experimental access to fermionic bulk dynamics in emulated AdS$_2$ spacetime with Lorentzian signature. This establishes a scalable analog platform that may potentially be used for exploring dynamical aspects of holography.

physics.optics↗

arXiv2025

Optical Tautochrone and Squeezing Dynamics in Nonuniform Lattices

We present exact analogies between the tautochrone problem of classical mechanics and the squeezed states of quantum optics to optical lattices. Both phenomena emerge in the same physical system, that of waveguide arrays with nonuniform couplings. Extension to two dimensions yields Lissajous-type trajectories and multidirectional tautochrone focusing. Furthermore, we investigate the impact of Kerr nonlinearity and show that it determines the diffraction behavior, namely coherent-state-like or squeezed propagation. These quantum inspired classical lattices highlight the role of the coupling coefficients to beam engineering and light control in complex media.

physics.optics↗

arXiv2025

Observation of Joule-Thomson photon-gas expansion

In recent years, a self-consistent optical thermodynamic framework has emerged that offers a systematic methodology to understand, harness and exploit the complex collective dynamics of multimode nonlinear systems. These developments now allow consideration of a series of longstanding problems in optics, including the prospect of funnelling the entire power flowing in a multimode system into its ground state, for which no methodology currently exists. Here, we demonstrate an all-optical Joule-Thomson expansion process mediated by photon-photon interactions whereby the temperature of the optical gas drops abruptly to zero. Our experiments in various configurations of coupled multicore nonlinear waveguide arrangements illustrate how light undergoing expansion-induced cooling can be channelled from arbitrary input states into the fundamental mode with near-unity efficiency. We show that the stability of the post-expansion state is ensured through an irreversible process of energy conversion. The all-optical thermodynamic phenomena explored in this study may enable innovative techniques where various uncorrelated but identical sources are merged into a unified spatially coherent state, offering a route for direct beam combining.

physics.optics↗

arXiv2025

Engineering Non-Hermitian Quantum Evolution Using a Hermitian Bath Environment

Engineering quantum bath networks through non-Hermitian subsystem Hamiltonians has recently emerged as a promising strategy for qubit cooling, state stabilization, and fault-tolerant quantum computation. However, scaling these systems while maintaining precise control over their complex interconnections, especially in the optical domain, poses significant challenges in both theoretical modeling and physical implementation. In this work, drawing on principles from quantum and mathematical physics, we introduce a systematic framework for constructing non-Hermitian subsystems within entirely Hermitian photonic platforms. In particular, controlled exponential decay without actual absorption loss is realized in finite 1-D waveguide chains through discrete-to-continuum coupling and Lanczos transformations. Using this new methodology, we implement parity-time symmetric quantum systems and experimentally demonstrate that these artificial bath environments accurately replicate the dynamics of non-Hermitian arrangements in both single- and multi-photon excitation regimes. Since the non-Hermitian subsystem response deterministically arises from an artificially built Hermitian bath, the quantum evolution can be monitored via post-selection in this fully conservative configuration. This approach bridges the gap between theoretical models and experimental realizations, thus paving the way for exploiting quantum bath engineering in advanced information processing and emerging quantum technologies.

quant-ph↗

arXiv2025

Drive-induced Non-local Interactions and Topological Bulk Transport of Extended Doublons

The existence of boundary states and their protection against symmetry-preserving perturbations are a hallmark feature of topological systems. While this concept originally emerged in the context of sin-gle-particle phenomena in condensed-matter physics, particle interactions have recently been identi-fied as alternative means to establish topological phases. As a consequence, nonlinear topological insu-lators gained much interest as a model system for many interacting particles. However, as their mean-field model inevitably breaks down for small numbers of particles, to date, topological states composed of only few interacting particles remain experimentally largely unexplored. In our work, we explore the physics of extended interaction-induced two-particle topological states, so-called Dou-blons. We experimentally implement non-local-interactions via non-adiabatic periodic driving and dimensional mapping in an artificial photonic solid. The resonant formation of extended Doublon qua-si-particles at specific local interaction strengths is observed, allowing us to probe the topologically protected motion of these entities through the bulk of the system. Our approach is compatible to a number of established experimental platforms and paves the way for studying topological few-particle phenomena with finite interaction strength.

physics.optics↗

arXiv2025

Pairing particles into holonomies

Holonomies are of great interest to quantum computation and simulation. The geometrical nature of these entities offers increased stability to quantum gates. Furthermore, symmetries of particle physics are naturally reflected in holonomies, making them ideally suited for quantum simulation of quantum chromodynamics and grand unified theories. Yet, practically designing quantum holonomies with the required properties and scale is challenging. Here, we construct a new class of holonomies by increasing the particle number. We show that multi-particle holonomies can even exist in systems devoid of any single-particle holonomies. We present a comprehensive framework for multi-particle quantum holonomies and experimentally realize various two-particle holonomies in integrated photonics. Our results enable particle number to be harnessed as a design parameter, offering increased freedom in constructing holonomies for quantum computation and simulation.

quant-ph↗

arXiv2025

Selective Filtering of Photonic Quantum Entanglement via Anti-Parity-Time Symmetry

Entanglement is a key resource for quantum computing, sensing, and communication, however it is highly susceptible to decoherence. To address this, quantum optics has explored filtering techniques like photon ancillas and Rydberg atom blockade to restore entangled states. Here, we introduce a an entirely new approach to entanglement retrieval exploiting non-Hermitian systems. By employing an anti-parity-time two-state guiding configuration, we demonstrate efficient extraction of entanglement from any input state. This filter is implemented on a lossless waveguide network using Lanczos transformations, consistent with Wigner-Weisskopf theory. This scheme achieves near-unity fidelity under single- and two-photon excitation and is scalable to higher photon levels while remaining robust against decoherence during propagation. Our work offers new insights into using non-Hermitian symmetries to address central challenges in quantum technologies.

quant-ph↗

arXiv2025

Eigenmodes of latent-symmetric quantum photonic networks

We investigate the impact of latent symmetries on the dynamics of photonic systems and their eigenmodes. Residing solely within the eigenspectral domain, latent symmetries are not visible in real space, yet promise intriguing new ways to engineer the functionality of photonic systems. We study the eigenmodes of a 9-site latent-symmetric photonic network and find that an anti-symmetric input state is fundamentally precluded from populating so-called singlet sites. Furthermore, arbitrary extensions of the system at these sites do not break its latent symmetry. Therefore anti-symmetric excitations cannot leave the initial system, which can be leveraged e.g. for the storage of information. This holds true for both single-photon states, or classical light, as well as both distinguishable and indistinguishable two-photon quantum states. Latent symmetries introduce a powerful new set of tools to the design of systems with desired functionality on any nanophotonic platform, paving the way for applications in photonic information processing.

physics.optics↗

arXiv2025

State Transfer in Latent-Symmetric Networks

The transport of quantum states is a crucial aspect of information processing systems, facilitating operations such as quantum key distribution and inter-component communication within quantum computers. Most quantum networks rely on symmetries to achieve an efficient state transfer. A straightforward way to design such networks is to use spatial symmetries, which severely limits the design space. Our work takes a novel approach to designing photonic networks that do not exhibit any conventional spatial symmetries, yet nevertheless support an efficient transfer of quantum states. Paradoxically, while a perfect transfer efficiency is technically unattainable in these networks, a fidelity arbitrarily close to unity is always reached within a finite time of evolution. Key to this approach are so-called latent, or 'hidden', symmetries, which are embodied in the spectral properties of the network. Latent symmetries substantially expand the design space of quantum networks and hold significant potential for applications in quantum cryptography and secure state transfer. We experimentally realize such a nine-site latent-symmetric network and successfully observe state transfer between two sites with a measured fidelity of 75%. Furthermore, by launching a two-photon state, we show that quantum interference is preserved by the network. This demonstrates that the latent symmetries enable efficient quantum state transfer, while offering greater flexibility in designing quantum networks.

quant-ph↗

arXiv2024

Benchmarking Analytical Query Processing in Intel SGXv2

Trusted Execution Environments (TEEs), such as Intel's Software Guard Extensions (SGX), are increasingly being adopted to address trust and compliance issues in the public cloud. Intel SGX's second generation (SGXv2) addresses many limitations of its predecessor (SGXv1), offering the potential for secure and efficient analytical cloud DBMSs. We assess this potential and conduct the first in-depth evaluation study of analytical query processing algorithms inside SGXv2. Our study reveals that, unlike SGXv1, state-of-the-art algorithms like radix joins and SIMD-based scans are a good starting point for achieving high-performance query processing inside SGXv2. However, subtle hardware and software differences still influence code execution inside SGX enclaves and cause substantial overheads. We investigate these differences and propose new optimizations to bring the performance inside enclaves on par with native code execution outside enclaves.

cs.DB↗

arXiv2024

Crossing exceptional points in non-Hermitian quantum systems

Exceptional points facilitate peculiar dynamics in non-Hermitian systems. Yet, in photonics, they have mainly been studied in the classical realm. In this work, we reveal the behavior of two-photon quantum states in non-Hermitian systems across the exceptional point. We probe the lossy directional coupler with an indistinguishable two-photon input state and observe distinct changes of the quantum correlations at the output as the system undergoes spontaneous breaking of parity-time symmetry. Moreover, we demonstrate a switching in the quantum interference of photons directly at the exceptional point, where Hong-Ou-Mandel dips are transformed into peaks by a change of basis. These results show that quantum interference and exceptional points are linked in curious ways that can now be further explored.

quant-ph↗

arXiv2024

Non-adiabatic holonomies as photonic quantum gates

One of the most promising nascent technologies, quantum computation faces a major challenge: The need for stable computational building blocks. We present the quantum-optical realization of non-adiabatic holonomies that can be used as single-qubit quantum gates. The hallmark topological protection of non-Abelian geometric phases reduces the need for quantum error correction on a fundamental physical level, while the inherent non-adiabaticity of the structures paves the way for unprecedented miniaturization. To demonstrate their versatility, we realize the Hadamard and Pauli-X gates, experimentally show their non-Abelian nature, and combine them into a single-qubit quantum algorithm, the PQ penny flipover. The planar geometry of such designs enables them to be substituted for the conventional directional coupler meshes currently in wide-spread use in photonic quantum architectures across all platforms.

quant-ph↗

arXiv2023

Order-invariant two-photon quantum correlations in PT-symmetric interferometers

Multiphoton correlations in linear photonic quantum networks are governed by matrix permanents. Yet, surprisingly few systematic properties of these crucial algebraic objects are known, while their calculation is a computationally hard task. As such, predicting the overall multiphoton behavior of a network from its individual building blocks typically defies intuition. In this work we identify sequences of concatenated two-mode linear optical transformations whose two-photon behavior is invariant under reversal of the order. We experimentally verify this systematic behavior in parity-time-symmetric complex interferometer arrangements of varying composition. Our results underline new ways in which quantum correlations may be preserved in counterintuitive ways even in small-scale non-Hermitian networks.

quant-ph↗

arXiv2022

Supersymmetric reshaping and higher-dimensional rearrangement of photonic lattices

Integrated Jx photonic lattices, inspired by the quantum harmonic oscillator and due to their equidistant eigenvalue spectrum, have been proven extremely useful for various applications, such as perfect imaging and coherent transfer of quantum states. However, to date their large-scale implementation remains challenging. We apply concepts from supersymmetry to construct two-dimensional (2D) systems with spectra identical to that of one-dimensional (1D) Jx lattices. While exhibiting different dynamics, these 2D systems retain the key imaging and state transfer properties of the 1D Jx lattice. Our method extends to other systems with separable spectra, facilitates experimental fabrication, and may increase robustness to fabrication imperfections in large-scale photonic circuits.

physics.optics↗

arXiv2022

Bimorphic Floquet Topological Insulators

Topological theories have established a new set of rules that govern the transport properties in a wide variety of wave-mechanical settings. In a marked departure from the established approaches that induce Floquet topological phases by specifically tailored discrete coupling protocols or helical lattice motions, we introduce a new class of bimorphic Floquet topological insulators that leverage connective chains with periodically modulated on-site potentials to unlock new topological features in the system. In exploring a 'chain-driven' generalization of the archetypical Floquet honeycomb lattice, we identify a rich phase structure that can host multiple non-trivial topological phases associated simultaneously with both Chern-type and anomalous chiral states. Experiments carried out in photonic waveguide lattices reveal a unique and strongly confined helical edge state that, owing to its origin in bulk flat bands, can be set into motion in a topologically protected fashion, or halted at will, without compromising its adherence to individual lattice sites.

physics.optics↗

arXiv2022

Three-dimensional photonic topological insulator induced by lattice dislocations

The hallmark of topological insulators is the scatter-free propagation of waves in topologically protected edge channels. This transport is strictly chiral on the outer edge of the medium, and therefore capable of bypassing sharp corners and imperfections, even in the presence of substantial disorder. In photonics, two-dimensional topological edge states have been demonstrated on several different platforms, and are emerging as a promising tool for robust lasers, quantum devices, and other applications. However, three-dimensional photonic topological insulators, specifically those supporting topologically protected edge states in all 3D, have thus far remained out of experimental reach. Here, we demonstrate a three-dimensional photonic topological insulator with protected topological edge states. The topological protection is enabled by a screw dislocation. For this purpose, we utilize the concept of synthetic dimensions in a 2D photonic waveguide array by introducing an additional modal dimension to transform the system into a 3D photonic topological insulator. The lattice dislocation endows the system with edge states propagating along three-dimensional trajectories, with topological protection akin to strong photonic topological insulators. Our work paves the way for utilizing three-dimensional topology in photonic science and technology.

physics.optics↗

arXiv2022

Populating and probing protected edge states through topology-entailed trivial states

Topological insulators enable non-reciprocal light propagation that is insensitive to disorder and imperfections. Yet, despite considerable attention from the photonics community and beyond, the very feature that has inspired numerous proposals for applications of topological transport also turns out to be one of the main stumbling blocks for practical implementations: Accessing topologically protected states is generally assumed to require their protection to be lifted. We overcome this limitation by topology-entailed trivial (TET) states that arise from the hybridization of counter-propagating interface states. We demonstrate selective injection and extraction of light into topological states as well as long-range coherent light exchange between spatially separated topological channels. Our results highlight the potential of TET states as protection-preserving paradigm to manipulate the flow of light in topological platforms.

physics.optics↗