Nanoassembly technique of carbon nanotubes for hybrid circuit-QED

掺杂碳纳米管中原子-场强耦合作用下的范德华能

van der Waals energy under strong atom-field coupling in doped carbon nanotubes

利用统一的宏观QED理论，我们导出了碳纳米管附近二能级原子系统的范德华能量的积分方程。该方程对强、弱原子-真空-光场耦合均成立。通过数值求解，我们证明了弱耦合范德华相互作用模型在纳米管表面附近的不适用性。

Highly coherent spin states in carbon nanotubes coupled to cavity photons

Spins confined in quantum dots are considered as a promising platform for quantum information processing. While many advanced quantum operations have been demonstrated, experimental as well as theoretical efforts are now focusing on the development of scalable spin quantum bit architectures. One particularly promising method relies on the coupling of spin quantum bits to microwave cavity photons. This would enable the coupling of distant spins via the exchange of virtual photons for two qubit gate applications, which still remains to be demonstrated with spin qubits. Here, we use a circuit QED…

Ultra-Efficient Coupling of a Quantum Emitter to the Tunable Guided Plasmons of a Carbon Nanotube

We show that a single quantum emitter can efficiently couple to the tunable plasmons of a highly doped single-wall carbon nanotube (SWCNT). Plasmons in these quasi-one-dimensional carbon structures exhibit deep subwavelength confinement that pushes the coupling efficiency close to 100% over a very broad spectral range. This phenomenon takes place for distances and tube diameters comprising the nanometer and micrometer scales. In particular, we find a beta factor ~1 for QEs placed 1-100 nm away from SWCNTs that are just a few nanometers in diameter, while the corresponding Purcell factor exceed…

Realization of a Carbon-Nanotube-Based Superconducting Qubit

Hybrid circuit quantum electrodynamics (QED) involves the study of coherent quantum physics in solid state systems via their interactions with superconducting microwave circuits. Here we present an implementation of a hybrid superconducting qubit that employs a carbon nanotube as a Josephson junction. We realize the junction by contacting a carbon nanotube with a superconducting Pd/Al bi-layer, and implement voltage tunability of the qubit frequency using a local electrostatic gate. We demonstrate strong dispersive coupling to a coplanar waveguide resonator via observation of a resonator frequ…

量子点、费米子引线和微波腔的片上耦合

Coupling a quantum dot, fermionic leads and a microwave cavity on-chip

我们展示了一个混合架构，由一个量子点电路耦合到一个单一的模式的电磁场。我们使用单壁碳纳米管为基础的电路插入超导微波腔。通过探测的纳米管点使用色散读出的库仑阻塞和近藤制度，我们确定的电子-光子耦合强度，使电路QED实验与更复杂的量子点电路。

Cavity photons as a probe for charge relaxation resistance and photon emission in a quantum dot coupled to normal and superconducting continua

Microwave cavities have been widely used to investigate the behavior of closed few-level systems. Here, we show that they also represent a powerful probe for the dynamics of charge transfer between a discrete electronic level and fermionic continua. We have combined experiment and theory for a carbon nanotube quantum dot coupled to normal metal and superconducting contacts. In equilibrium conditions, where our device behaves as an effective quantum dot-normal metal junction, we approach a universal photon dissipation regime governed by a quantum charge relaxation effect. We observe how photon …