The large available Hilbert space and high coherence of cavity resonators makes these systems an interesting resource for storing encoded quantum bits. To perform a quantum gate on this encoded information, however, complex nonlinear operations must be applied to the many levels of the oscillator simultaneously. In this work, we introduce the Selective Number-dependent Arbitrary Phase (SNAP) gate, which imparts a different phase to each Fock state component using an off-resonantly coupled qubit. We show that the SNAP gate allows control over the quantum phases by correcting the unwanted phase evolution due to the Kerr effect. Furthermore, by combining the SNAP gate with oscillator displacements, we create a one-photon Fock state with high fidelity. Using just these two controls, one can construct arbitrary unitary operations, offering a scalable route to performing logical manipulations on oscillator-encoded qubits.
The pseudospin of heavy-holes (HHs) confined in a semiconductor quantum dot (QD) represents a promising candidate for a fast and robust qubit. While hole spin manipulation by a classical electric field utilizing the Dresselhaus spin-orbit interaction (SOI) has been demonstrated, our work explores cavity-based qubit manipulation and coupling schemes for inversion-symmetric crystals forming a planar HH QD. Choosing the exemplary material Germanium (Ge), we derive an effective cavity-mediated ground state spin coupling that harnesses the cubic Rashba SOI. In addition, we propose an optimal set of…
Ensembles of ultra-cold atoms have been proven to be versatile tools for high precision sensing applications. Here, we present a method for manipulation and readout of the state of trapped clouds of ultra-cold bosonic atoms. In particular, we discuss the creation of coherent and squeezed states of quasiparticles and the coupling of quasiparticle modes through an external cavity field. This enables operations like state swapping and beam splitting which can be applied to realize a Mach-Zehnder interferometer (MZI) in frequency space. We present two explicit example applications in sensing: the …
A cavity-mediated reconfigurable coupling scheme for superconducting qubits
Pritzker School of Molecular Engineering, University of Chicago（芝加哥大学普里茨克分子工程学院）；Institute of Applied Physics, Seoul National University（首尔国立大学应用物理研究所）；NextQuantum Innovation Research Center, Seoul National University（首尔国立大学NextQuantum创新中心）；Department of Physics and Astronomy, Seoul National University（首尔国立大学物理与天文学系）
We investigate optimal states of photon pairs to excite a target transition in a multilevel quantum system. With the help of coherent control theory for two-photon absorption with quantum light, we infer the maximal population achievable by optimal entangled vs. separable states of light. Interference between excitation pathways, as well as the presence of nearby states, may hamper the selective excitation of a particular target state, but we show that quantum correlations can help to overcome this problem, and enhance the achievable "selectivity" between two energy levels, i.e. the relative d…
Manipulation of Arbitrary-Order Cavity-Magnon Polariton Blockade
Fujian Key Laboratory of Quantum Information and Quantum Optics, College of Physics and Information Engineering, Fuzhou University（福建量子信息与光学重点实验室，福州大学物理与信息工程学院）
Channel-selective frequency up-conversion for frequency-multiplexed quantum network
Graduate School of Engineering Science, Osaka University（大阪大学工学研究科）；Center for Quantum Information and Quantum Biology, Osaka University（大阪大学量子信息与量子生物学中心）
State-selective coherent motional excitation as a new approach for the manipulation, spectroscopy and state-to-state chemistry of single molecular ions
Light extraction from CVD-grown <400> single crystal diamond nanopillars. Selective charge state manipulations with 0V SF6 plasma
我们研究了从单晶金刚石纳米柱中实现光提取的可能性。这是通过专用的519 nm激光诱导带负电荷的氮空位（NV-）的自旋态引发来实现的。对于第一次，我们提出的可能性，以执行有效的自旋读出NV（-）的自然产生的生长过程中的化学气相沉积（CVD）合成SCD内没有任何后生长注入策略。应用的金刚石既没有注入14 N+，也没有CVD合成的SCD退火，使得氮空位的存在是一个显着的现象。为了研究在室温和环境条件下利用NV（-）明亮的光致发光和波导效应实现光提取的可能性，我们通过电子束光刻（EBL）和干法电感耦合等离子体/反应离子刻蚀（ICP-RIE）进行了SCD的自顶向下纳米加工，以产生光聚焦纳米柱。此外，我们还通过专用的0 V ICP等离子体对金刚石表面进行了氟化处理。光提取和自旋操纵进行光致发光（PL）光谱和光学检测磁共振（ODMR）在室温下。我们已经观察到基于选择性0 V SF6等离子体蚀刻的显著效果，并且令人惊讶地，与文献发现相反，NV（-）中心的失活。我们详细讨论了可能的失活机制，关于二维空穴气（2 HG）和费米带弯曲。
Subspace-selective unitary manipulation based on the Hilbert-space symmetric structures in the multiple-quantum operator algebra spaces in the quantum-computing speedup theory
We present an error-detected hyperparallel Toffoli (hyper-Toffoli) gate for a three-photon system based on the interface between polarized photon and cavity-nitrogen-vacancy(NV) center system. This hyper-Toffoli gate can be used to perform double Toffoli gate operations simultaneously on both the polarization and spatial-mode degrees of freedom (DoFs) of a three-photon system with a low decoherence, shorten operation time, and less quantum resources required, in compared with those on two independent three-photon systems in one DoF only. As the imperfect cavity-NV-center interactions are trans…
