Lightwave Terahertz Quantum Manipulation of Non-equilibrium Superconductor Phases and their Collective Modes

Abstract

We present a gauge-invariant density matrix description of non-equilibrium superconductor (SC) states with spatial and temporal correlations driven by intense terahertz (THz) lightwaves. We derive superconductor Bloch--Maxwell equations of motion that extend Anderson pseudo-spin models to include the Cooper pair center-of-mass motion and electromagnetic propagation effects. We thus describe quantum control of dynamical phases, collective modes, quasi-particle coherence, and high nonlinearities during cycles of carrier wave oscillations, which relate to our recent experiments. Coherent photogeneration of a nonlinear supercurrent with dc component via condensate acceleration by an effective lightwave field dynamically breaks the equilibrium inversion symmetry. Experimental signatures include high harmonic light emission at equilibrium-symmetry-forbidden frequencies, Rabi--Higgs collective modes and quasi-particle coherence, and non-equilibrium moving condensate states tuned by few-cycle THz fields. We use such lightwaves as an oscillating accelerating force that drives strong nonlinearities and anisotropic quasi-particle populations to control and amplify different classes of collective modes, e.g., damped oscillations, persistent oscillations, and overdamped dynamics via Rabi flopping. Recent phase-coherent nonlinear spectroscopy experiments can be modeled by solving the full nonlinear quantum dynamics including self-consistent light--matter coupling.

19 pages, 11 figures

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Cited by in corpus (9)

• Dynamical phase transitions in the collisionless pre-thermal states of isolated quantum systems: theory and experiments
• Quantum Coherence Tomography of Lightwave Controlled Superconductivity
• Light Quantum Control of Persisting Higgs Modes in Iron-Based Superconductors
• Multi-Dimensional Coherent Spectroscopy of Light-Driven States and their Collective Modes in Multi-Band Superconductors
• Engineering Higgs dynamics by spectral singularities
• Interplay between nematicity and Bardasis-Schrieffer modes in the short-time dynamics of unconventional superconductors
• Discovery of an Unconventional Quantum Echo by Interference of Higgs Coherence
• Signatures of Bardasis-Schrieffer mode excitation in Third-Harmonic generated currents
• Chirped pulse control over the melting of superconductors