Quantum Interfaces to the Nanoscale

Defect Polaritons from First Principles

“…Both methods, however, are computationally expensive for the hundreds of atoms necessary to simulate a defect in a bulklike material. Finally, we anticipate that applying these first-principles-based approaches to spin-polarized systems to be especially fruitful for engineering quantum technological systems, such as NV and SiV – defect centers in diamond where logical qubits are often mapped to the spin state in the ground-state manifold that operate in the GHz range and can be coupled to host lattice phonons, magnetic fields, and microwaves …”

“…Finally, we anticipate that applying these first-principles-based approaches to spinpolarized systems to be especially fruitful for engineering quantum technological systems, such as NV and SiV − defect centers in diamond where logical qubits are often mapped to the spin state in the ground-state manifold that operate in the GHz range and can be coupled to host lattice phonons, magnetic fields, and microwaves. 15 Given the large shifts in absorption frequency, large increases in transition dipole moments, and delocalization of the electronic transition density due to coupling between the electronic continuum and the cavity mode, coupling defect systems to optical cavities to form defect polaritons may be a powerful control knob for tuning the optical properties of defects for quantum technological applications. We predict these properties of defect polaritons with a first-principles method that encapsulates the full complexity of the electronic structure of defects in a solid-state material, highlighting the importance of electronic structure techniques in the development of quantum optical materials.…”

“…Defects in solid-state materials have wide applicability in scalable and stable solid-state quantum technologies. − They are especially suitable as quantum memories , or as quantum transducers because they can interact with a wide range of quantum information carriers, such as phonons, magnons, and photons, across a broad spectral range. − These defects, including simple substitutional or vacancy defects, as well as hybridized defect complexes, − can introduce spatially localized electronic states whose electronic, optical, and spin properties can be tuned by coupling them to external fields, including electric, magnetic, and strain fields, as well as to waveguides and cavity environments. ,− Due to their flexible applications, demands to the properties of defect systems are ever-increasing, such as specific level structures for the emission of entangled photonic states , or implementation of multiqubit photonic gates…”

Entangled photons from composite cascade emitters

“…Ab initio computation of eigenstates of, eigenenergies of, and transtions between multiply excited state is a challenging problem [39], thereby highlighting the major benefit of this toy model-driven approach to guiding rational design of composite emitters. The present method can accelerate optimization of composite emitters for applications with many constraints on frequency-entangled photons, such as quantum networking [5,20,40], where optical, mid-infrared, and microwave photons are relevant for on-chip computation, transmission across long distances, and coupling to other qubit types [41], such as superconducting qubits, respectively.…”

Defect polaritons from first principles

“…Defect emitters in solid-state materials have wide applicability in scalable and stable solid-state quantum technologies [1][2][3][4][5][6][7]. They are especially suitable as quantum memories [8,9] or as quantum transducers because they can interact with a wide range of quantum information carriers, such as phonons, magnons, and photons, across a broad spectral range [10][11][12][13][14][15]. These defectsincluding simple substitutional or vacancy defects, as well as hybridized defect complexes [16][17][18][19]-can introduce spatially localized electronic states whose electronic, optical, and spin properties can be tuned by coupling them to external fields, including electric, magnetic, and strain fields, as well as to waveguides and cavity environments [14,[20][21][22][23][24][25][26].…”