A5015112349- Physics of Superconductivity and Magnetism
- Cold Atom Physics and Bose-Einstein Condensates
- Spectroscopy and Quantum Chemical Studies
- Quantum and electron transport phenomena
- Strong Light-Matter Interactions
- Mechanical and Optical Resonators
- Quantum Electrodynamics and Casimir Effect
- Quantum, superfluid, helium dynamics
- 2D Materials and Applications
- Topological Materials and Phenomena
- Iron-based superconductors research
- Advanced Chemical Physics Studies
- Chalcogenide Semiconductor Thin Films
- Quantum many-body systems
- Dust and Plasma Wave Phenomena
- Magnetic properties of thin films
- Quantum Information and Cryptography
- Advanced Thermodynamics and Statistical Mechanics
- Quantum optics and atomic interactions
- Geophysics and Sensor Technology
- Photonic and Optical Devices
- Advanced Physical and Chemical Molecular Interactions
- Plasmonic and Surface Plasmon Research
- Magnetic Bearings and Levitation Dynamics
- Spectral Theory in Mathematical Physics
Max Planck Institute for the Structure and Dynamics of Matter
2023-2024
Harvard University
2019-2024
Center for Free-Electron Laser Science
2024
Universität Hamburg
2024
The excitonic insulator is an electronically driven phase of matter that emerges upon the spontaneous formation and Bose condensation excitons. Detecting this exotic order in candidate materials a subject paramount importance, as size gap band structure establishes potential collective state for superfluid energy transport. However, identification real solids hindered by coexistence structural parameter with same symmetry order. Only few are currently believed to host dominant phase, Ta 2...
Abstract Optical driving of materials has emerged as a versatile tool to control their properties, with photo-induced superconductivity being among the most fascinating examples. In this work, we show that light or lattice vibrations coupled an electronic interband transition naturally give rise electron-electron attraction may be enhanced when underlying boson is driven into non-thermal state. We find phenomenon resonantly amplified tuning boson’s frequency close energy difference between...
Upon excitation by a laser pulse, broken-symmetry phases of wide variety solids demonstrate similar order parameter dynamics characterized dramatic slowing down relaxation for stronger pump fluences. Motivated this recurrent phenomenology, we develop simple non-perturbative effective model collective bosonic excitations in pump-probe experiments. We find that as the system recovers after photoexcitation, it shows universal prethermalized manifesting power-law, opposed to exponential,...
Abstract A number of experiments have evidenced signatures enhanced superconducting correlations after photoexcitation. Initially, these were interpreted as resulting from quasi-static changes in the Hamiltonian parameters, for example, due to lattice deformations or melting competing phases. Yet, several recent observations indicate that conjectures are either incorrect do not capture all observed phenomena, which include reflectivity exceeding unity, large shifts Josephson plasmon edges,...
Non-linear interactions between collective modes play a definitive role in far out of equilibrium dynamics strongly correlated electron systems. Understanding and utilizing these is crucial to photo-control quantum many-body states. One the most surprising examples strong mode coupling interaction apical oxygen phonons Josephson plasmons bilayer YBa$_2$Cu$_3$O$_{6+x}$ superconductors. Experiments by Hu et al (2014). Kaiser al. (2014) showed that below Tc, photo-excitation leads enhancement...
We present a novel theoretical approach for computing and analyzing two-dimensional spectroscopy of bosonic collective excitations in disordered many-body systems. Specifically, we employ the Keldysh formalism to derive nonlinear response obtain maps with particular emphasis on rephasing sector, which allows disentangle different sources broadening. Our successfully distinguishes elastic inelastic scattering mechanisms contributing excitation linewidth. Additionally, using non-perturbative...
Photonic time crystals refer to materials whose dielectric properties are periodic in time, analogous a photonic crystal is space. Here, we theoretically investigate time-crystalline behaviour initiated by optical excitation above the electronic gap of excitonic insulator candidate Ta
The excitonic insulator is an electronically-driven phase of matter that emerges upon the spontaneous formation and Bose condensation excitons. Detecting this exotic order in candidate materials a subject paramount importance, as size gap band structure establishes potential collective state for superfluid energy transport. However, identification real solids hindered by coexistence structural parameter with same symmetry order. Only few are currently believed to host dominant phase,...
Recent experimental realizations of uniform confining potentials for ultracold atoms make it possible to create quantum acoustic resonators and explore nonequilibrium dynamics field theories. These systems offer a promising platform studying the dynamical Casimir effect, since they allow one achieve relativistic, i.e., near sonic, velocities boundaries. In comparison previously studied optical classical hydrodynamic systems, realize broader class experiments combining both driving vacuum...
Control of quantum matter through resonant electromagnetic cavities is a promising route towards establishing control over material phases and functionalities. Quantum paraelectric insulators---materials that are nearly ferroelectric---are particularly candidate systems for this purpose since they have strongly fluctuating collective modes directly couple to the electric field. In work, we explore possibility in system comprised sandwiched between two high-quality metal mirrors, realizing...
Two-dimensional terahertz spectroscopy (2DTS), a analogue of nuclear magnetic resonance, is new technique poised to address many open questions in complex condensed matter systems. The conventional theoretical framework used ubiquitously for interpreting multidimensional spectra discrete quantum level systems is, however, insufficient the continua collective excitations strongly correlated materials. Here, we develop theory 2DTS model excitation, Josephson plasma resonance layered...
Inhomogeneities play a crucial role in determining the properties of quantum materials. Yet methods that can measure these inhomogeneities are few, and apply to only fraction relevant microscopic phenomena. For example, electronic cuprate materials known be inhomogeneous over nanometer length scales, although questions remain about how such disorder influences supercurrents their dynamics. Here, two-dimensional terahertz spectroscopy is used study interlayer superconducting tunneling...
<title>Abstract</title> Periodic laser driving, known as Floquet engineering, is a powerful tool to manipulate the properties of quantum materials. Using circularly polarised light, artificial magnetic fields, called Berry curvature, can be created in photon-dressed Floquet-Bloch states that form. This mechanism, when applied 3D Dirac and Weyl systems, predicted lead movement nodes which should detectable transport sector. The response such topological light-matter hybrid, however, remains...
We discuss terahertz pump-probe experiments in hBN from the perspective of Floquet optical materials and photonic time crystals. Anisotropic nature this material results a large separation frequencies in-plane out-of-plane phonons leads to several branches phonon-polariton excitations. consider slab finite thickness pumped at frequency middle polaritons, around 25 THz. theoretically analyze properties pump induced state identify interesting features, including possible light amplification...
In the past decade, photo-induced superconducting-like behaviors have been reported in a number of materials driven by intense pump fields. Of particular interest is high-$T_c$ cuprate $\rm Y Ba_2 Cu_2 O_{6+x}$, where such effect has up to so-called pseudogap temperature $T^* \sim 300-400$ K. recent tour-de-force experiment, transient magnetic field which proportional and same direction an applied observed outside sample, suggestive flux exclusion due Meissner effect. this paper, we point...
A number of experiments have evidenced signatures enhanced superconducting correlations after photoexcitation. Initially, these were interpreted as resulting from quasi-static changes in the Hamiltonian parameters, for example, due to lattice deformations or melting competing phases. Yet, several recent observations indicate that conjectures are either incorrect do not capture all observed phenomena, which include reflectivity exceeding unity, large shifts Josephson plasmon edges, and...
Parametric resonances and amplification have led to extraordinary photo-induced phenomena in pump-probe experiments. While these manifest themselves out-of-equilibrium settings, here, we present the striking result of parametric equilibrium. In particular, demonstrate that quantum thermal fluctuations a Raman-active mode amplifies light inside cavity, at equilibrium, when Raman frequency is twice cavity frequency. This noise-driven leads creation an unusual polariton, intertwining with...
We performed infrared pump-terahertz probe spectroscopy on the excitonic insulator, Ta 2 NiSe 5 . Parametric amplification of an IR-active phonon exhibits order parameter-like temperature dependence, suggesting a novel approach to monitor exciton condensate dynamics.
Optical drives at terahertz and mid-infrared frequencies in quantum materials are increasingly used to reveal the nonlinear dynamics of collective modes correlated many-body systems their interplay with electromagnetic waves. Recent experiments demonstrated several surprising optical properties transient states induced by driving, including appearance photo-induced edges reflectivity cuprate superconductors, observed both below above equilibrium transition temperature. Furthermore, other...