VCQ Colloquium Summer Semester 2025

Towards an Artificial Muse for new ideas in Physics

Artificial intelligence (AI) is a potentially disruptive tool for physics and science in general. One crucial question is how this technology can contribute at a conceptual level to help acquire new scientific understanding or inspire new surprising ideas. I will talk about how AI can be used as an artificial muse in physics, which suggests surprising and unconventional ideas and techniques that the human scientist can interpret, understand and generalize to its fullest potential [1]. I will focus on AI for the design of new physics experiments, in the realm of quantum-optics [2, 3] and quantum-enhanced gravitational wave detectors [4] as well as super-resolution microscopy [5]. Finally I will discuss how algorithms with access to millions of scientific papers can predict and suggest future ideas for scientists [6,7].

[1] Krenn, Pollice, Guo, Aldeghi, Cervera-Lierta, Friederich, Gomes, Häse, Jinich, Nigam, Yao, Aspuru-Guzik, On scientific understanding with artificial intelligence. Nature Reviews Physics 4, 761 (2022).

[2] Krenn, Kottmann, Tischler, Aspuru-Guzik, Conceptual understanding through efficient automated design of quantum optical experiments. Physical Review X 11(3), 031044 (2021).

[3] Ruiz-Gonzalez, Arlt, et al., Digital Discovery of 100 diverse Quantum Experiments with PyTheus, Quantum 7, 1204 (2023).

[4] Krenn, Drori, Adhikari, Digital Discovery of interferometric Gravitational Wave Detectors, in press: Phys. Rev. X (2025), (https://arxiv.org/abs/2312.04258)

[5] Rodríguez, Arlt, Möckl, Krenn, Automated discovery of experimental designs in super-resolution microscopy with XLuminA, Nature Comm. 15, 10658 (2024)

[6] Krenn et al., Forecasting the future of artificial intelligence with machine learning-based link prediction in an exponentially growing knowledge network, Nature Machine Intelligence 5, 1326 (2023)

[7] Gu, Krenn, Interesting Scientific Idea Generation Using Knowledge Graphs and LLMs: Evaluations with 100 Research Group Leaders. arXiv:2405.17044 (2024)

Quantum Sensor Networks

Entangling quantum sensors, such as magnetometers or interferometers, can dramatically increase their sensitivity. In this talk, we will discuss how entanglement in a network of quantum sensors can be used to accurately measure one or more properties of spatially varying fields, including spatially correlated noise.

Quantum Processors and Quantum Networks – Atom-by-Atom

Reconfigurable arrays of neutral atoms have emerged as a leading platform for quantum science. Their excellent coherence properties combined with programmable Rydberg interactions have led to intriguing observations such as quantum phase transitions, the discovery of quantum many-body scars, and novel quantum computing architectures.

Here, I will look forward to what is next for atom arrays. In particular, I am going to introduce a dual-species Rydberg array, that naturally lends itself for measurement-based protocols such as quantum error correction, long-range entangled state preparation, and measurement-altered many-body dynamics. The second atomic species is used as an auxiliary qubit to measure and control the primary species. In a first demonstration of this architecture, we use an array of cesium qubits to correct correlated phase errors on an array of rubidium data qubits [1]. Rydberg interactions between the two species then lead to novel regimes, including greatly enhanced resonant dipole interactions, that we use to demonstrate a two-qubit gate and quantum non-demolition readout [2].

Another crucially important step for atom arrays will be the scaling beyond a single processing module. I will describe how a modular quantum network architecture can look like and will present a node that combines large atom arrays with arrays of photonic interfaces at telecom wavelength [3].

[1] Singh, Bradley, Anand, Ramesh, White, Bernien, Science (2023)

[2] Anand, Bradley, White, Ramesh, Singh, Bernien, Nature Physics (2024)

[3] Menon, Glachman, Pompili, Dibos, Bernien, Nature Comm. (2024)

Electronic Fingerprint Spectroscopy with Frequency Combs

Dual Comb Spectroscopy (DCS) combines high spectral resolution with broad spectral coverage and short measurement times. In the recent years, this spectroscopic method has proven its capabilities in molecular spectroscopy in different spectral regions ranging from the visible across the infrared spectral region into the THz domain [1-3]. The UV has so far been neglected for fingerprinting although electron transitions are as element specific as rovibrational transitions and the corresponding absorption cross sections can be huge (> 100 Mb). Additionally, DCS combined with pump probe sample interaction provides a unique combination of ultra-high spectral (GHz) and high temporal (fs) resolution. This can explore photo-induced dynamics in atoms and molecules involving transient effects such as level splittings, shifts and quantum beatings at a new level of detail.

I will present our first efforts and latest results on expanding dual comb spectroscopy via nonlinear frequency up-conversion into the ultraviolet region [4-6]. Further application possibilities aim at environmental sensing in the field [7] and in real time [8].

[1] Bernhardt, A. Ozawa, P. Jacquet, M. Jacquey, Y. Kobayashi, T. Udem, R. Holzwarth, G. Guelachvili, T. W. Hänsch, and N. Picqué, „Cavity-enhanced dual-comb spectroscopy,“ Nature Photonics 4, 55–57 (2009).

[2] T. Ideguchi, S. Holzner, B. Bernhardt, G. Guelachvili, N. Picqué, and T. W. Hänsch, „Coherent Raman spectro-imaging with laser frequency combs.,“ Nature 502, 355–8 (2013).

[3] G. Hu, T. Mizuguchi, R. Oe, K. Nitta,X. Zhao, T. Minamikawa, T. Li, Z. Zheng and T. Yasui, “Dual terahertz comb spectroscopy with a single free-running fibre laser”, Scientific Reports 8, 11155 (2018)

[4] V. Schuster, C. Liu, R. Klas, P. Dominguez, J. Rothhardt, J. Limpert, and B. Bernhardt, “Ultraviolet dual comb spectroscopy: a roadmap”, Optics Express 29, Issue 14, 21859-21875 (2021)

[5] Fürst, L., Kirchner, A., Eber, A., Siegrist, F., Di Vora, R., and Bernhardt, B., Broadband near-ultraviolet dual comb spectroscopy, (2024), Optica, Vol. 11, Issue 4, 471, (2024)

[6] L. Fürst, A. Eber, M. Pal, E. Hruska, C. Hofmann, I. Gordon, M. Schultze, R. Breinbauer, B. Bernhardt, Ultra-resolution photochemical sensing, arXiv:2501.07350 (2025)

[7] A. Eber, L. Fürst, F. Siegrist, A. Kirchner, B. Tschofenig, B., R. Di Vora, A. Speletz and  B. Bernhardt Coherent field sensing of nitrogen dioxide, Optics Express, Vol. 32, Issue 4, pp. 6575-6586 (2024)

[8] A. Eber, Ch. Gruber, M. Schultze, B. Bernhardt and M. Ossiander, Streaming Self-Corrected Dual-Comb Spectrometer, https://doi.org/10.48550/arXiv.2503.07005 (2025)

Progress in electron-lattice dynamics, with application to the strange metals

We have developed quantum acoustics along the lines of quantum optics. Far from being of only pedagogical interest, it allows us to solve previously intractable electron-lattice vibration problems, by moving away from number state, particle (phonon) based theory to the coherent state, wave based picture.  Much strange metal physics has come into focus, within a basic Fröhlich Hamiltonian treated nonperturbatively and coherently.  A new many-body quantum acoustic mean field “wave-on-wave” code has seen Planckian resistivity,  polarons, and CDW form spontaneously on a laptop in solid state systems using strange metal parameters. We have found the transport to be Planckian diffusive in the strange metal phase, with perfectly linear in T resistivity.  We understand the transition to the pseudogap phase and will explain the quantum criticality and strong correlation so often cited in connection with the strange metals.  We have generalized Anderson localization to the case of active random media and discovered that Planckian diffusion results over very large parameter ranges.

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