The properties of molecules and solids derive from the quantum mechanics of the electrons and nuclei they are made of. As a full quantum many-body treatment is impractical, virtually all theories begin from the Born-Oppenheimer approximation, where the many-electron problem is solved under the assumption that the usually sluggish nuclei are fixed in space. Solving the many-electron problem again and again for different fixed nuclear positions maps out an electronic wave function Phi_R, a conditional probability amplitude, depending parametrically on the set of nuclear coordinates R.
Computer simulations based on the first principles calculations play a central role in helping us understand, predict, and engineer physical, chemical, and electronic properties of technologically relevant materials.
Atomically thin materials derived from layered crystals have occupied much of the condensed matter community since the discovery of graphene in 2004. Transition metal dichalcogenides (TMDs) are among the most versatile members in the family of layered materials due to the opportunities for tuning electronic behaviors with chemical composition, layer number, and structural phase.
Quantum materials are believed to be key for many next-generation technologies, such as sensing, computing, modeling or communication, with higher accuracy or efficiency. Particularly, the magnetic quantum materials are promising for spintronic applications due to the interplay of magnetic order with electronic properties. To study the intrinsic material properties and evaluate the performance of novel devices fabricated from these materials, a high material quality is necessary. Otherwise the desired properties might be obscured.
With recent demonstration of quantum computing and quantum communication, quantum information science has been changing our world in an unprecedented way. To fully explore the power of quantum information processing, it is important to further combine discrete quantum elements and build distributed quantum networks. However, this poses significant technical challenges because quantum coherence can be easily destroyed as the signal propagates through different systems.
In the race of post-CMOS computing technologies, coherent information processing with microwave circuits have demonstrated great potentials with the recent breakthrough in quantum computing, where both the quanta and the phase of the excitation states can be utilized for carrying and processing information. As one of the candidate excitations for coherent information processing, magnons are collective excitations of exchange-coupled spins in magnetic materials with the natural frequency lying in the microwave regime.