Interfacing Superconducting Qubits and Single Optical Photons Using Molecules in Waveguides

Abstract

We propose an efficient light-matter interface at optical frequencies between a single photon and a superconducting qubit. The desired interface is based on a hybrid architecture composed of an organic molecule embedded inside an optical waveguide and electrically coupled to a superconducting qubit placed near the outside surface of the waveguide. We show that high fidelity, photon-mediated, entanglement between distant superconducting qubits can be achieved with incident pulses at the single photon level. Such a low light level is highly desirable for achieving a coherent optical interface with superconducting qubit, since it minimizes decoherence arising from the absorption of light. 42.50.Ex, 85.25.Cp Rapid progress in engineering and control of their physical properties, have made superconducting (SC) qubits, one of the most promising candidates for future quantum processors [1][2][3][4]. If such processors are connected together into a quantum internet [5], it would allow immense applications ranging from secure communication over long distances [6][7][8] to distributed quantum computation [9][10][11] and advanced protocols for distributed sensing and atomic clocks [12]. Quantum communication over long distances can, however, only be accomplished through optical means making it a necessity to build light-matter interfaces at optical frequencies [5,13]. This has stimulated immense interest in devising ways of efficiently coupling optical photons to SC systems [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. Tremendous success have been achieved in coupling photons to SC qubit at microwave frequencies [30,31], while in the optical domain, only limited indirect coupling has been achieved using transducers [32][33][34]. Coherent coupling of quantum fields at optical frequencies to a SC system thus remains an outstanding challenge. A principle obstacle to this is the large mismatch between the energy scales of an optical photon (∼ 1 eV) and a SC qubit (∼ 100 µeV) [30] making the absorption of even a single optical photon a major disturbance for a SC system. In fact such effects are used in SC detectors for detection of optical photons [35]. To suppress such disturbances it is therefore highly desirable to keep the number of optical photons to a minimum.In this letter we propose a scheme to interface optical photons with a SC qubit at light levels involving only a single or a few photons. To achieve this we introduce a hybrid solidstate architecture depicted in Fig. 1(a) comprising, a molecule embedded in an optical waveguide with a SC qubit fabricated near its surface (∼ 100 − 500 nm). In comparison to the magnetic coupling considered previously [23-25, 31, 36-41], a key feature of our scheme is the electric coupling between the molecule and SC qubit. The coupling strength can then be orders of magnitude stronger thus allowing for strong coupling in the system. As the SC qubit we consider a Cooper pair box (CPB) where the two quantum states are defined by a single Cooper pair being on each o...

Characterization of Er3+:YVO4 for microwave to optical transduction

“…A primary example is to convert quantum states encoded in microwave photons to optical frequencies, which would enable distributed quantum computing schemes based on superconducting qubits or spin qubits [7]. Many physical systems have been proposed for microwave to optical (M2O) transduction [8,9], including optomechanical systems [10,11], electro-optical systems [12,13], atomic ensembles [14,15] and others [16,17]. Among the atomic ensemble approaches, rare-earth ions (REIs) in solids are a promising platform for M2O transduction applications [14,18,19,20,21].…”

“…More specifically, in the limit of adiabatic driving and low efficiency ( < 10 -2 ), the transduction efficiency scales as ≡ # $ %& $ %' ( '& ) * + * , -. [17], where 01 ( 01 ) is the optical (spin) dipole moment between levels and j of the 3-level system, is the number density of REIs, and Δ 7(() is the detuning from the atomic resonance in the optical (microwave) domain, as shown in Fig. 1.…”

Controllable quantum interface between itinerant optical photon and microwave photonic memory

“…By taking advantage of the low loss of silica in particular frequency range [8] the optical communication can be realized in the realistic quantum internet, yielding a possibility of transferring quantum information over long distance [9]. A lot of studies have been devoted to implementing the interface between itinerant optical photonic qubits and the memory qubits, such as NV centers [10][11][12], superconducting qubits [13][14][15][16] and cold atoms [17,18].…”

Spatially Adiabatic Frequency Conversion in Optoelectromechanical Arrays

“…As a result, transduction of quantum signals has attracted attention as an important task for quantum technologies [17] and various systems have been proposed as suitable candidates for mediating interaction between microwaves and light: Atomic, molecular, and solid-state impurity spins [18][19][20][21][22][23][24][25], magnons in ferromagnetic materials [26], electrooptic modulators [27][28][29][30], and mechanical oscillators [31][32][33][34][35][36][37][38][39] are all capable of interacting with both frequency domains. Particularly optoelectromechanical systems [see Fig.…”