Magnetic Schrödinger type equations are important physical models in the study of quantum electrodynamics (QED). This manuscript focuses on the regularity behavior of the solution of the stochastic hyperbolic equation influenced by various types of exponentially oscillating coefficients on the principal Hamiltonian operator part. Techniques from harmonic analysis and stochastic analysis are applied to explore the upper bound of loss of regularity. Moreover, appropriate counter-examples with periodic coefficients are constructed to show the lower bound of loss of regularity by the application of instability arguments.
K E Y W O R D Sexponentially oscillating coefficients, Hamiltonian operator, loss of regularity, instability argument, magnetic Schrödinger type hyperbolic equations
INTRODUCTIONAs is known, in the study of quantum mechanics, a magnetic field is produced by electric fields varying in time, spinning of the elementary particles, or moving electric charges, etc. Since last century, electromagnetic theory has been extensively utilized in the graphene research in magnetic fields, medical research of organs' biomagnetism, vortex study in the superconductor which carries quantized magnetic flux, and geographical forecasts for cataclysms, such as earthquakes, volcanic eruptions, geomagnetic reversal, etc. Magnetic Schrödinger type equations are important physical models in these respects [2,4,10,12]. In this background, we discuss the regularity of the solution of the magnetic Schrödinger hyperbolic equation with various types of oscillating coefficients of second-order moment stochastic processes. More importantly, we make a delicate classification of the oscillations with respect to the regularity behavior. Before introducing the main results, it is necessary to show some important relevant prerequisites.
Introduction to the pseudodifferential operators associated to the Hamiltonian operatorLet 𝐀 be the vector potential of the magnetic flux density 𝐁 in the magnetic field, which does not depend on time, namely, 𝐁 = ∇ × 𝐀. Clearly, ∇ ⋅ 𝐁 = div rot𝐀 = 0.We deduce from the Maxwell's equation (𝜇 is the magnetic permeability) ∇ × 𝐄 = −𝜇 𝜕𝐁 𝜕𝑡 = 0