Article
Nanoscience & Nanotechnology
Pierre-Andre Mortemousque, Emmanuel Chanrion, Baptiste Jadot, Hanno Flentje, Arne Ludwig, Andreas D. Wieck, Matias Urdampilleta, Christopher Bauerle, Tristan Meunier
Summary: Controlling individual quantum objects organized in arrays is essential for scalable quantum information platforms. By integrating nearest-neighbour coupled semiconductor quantum dots in a 3 x 3 array with finely tuned virtual gate control, 2D coherent spin control has been achieved. Recent efforts in controlling electron spins in quantum dot arrays have led to the realization of quantum simulators and multielectron spin-coherent manipulations. However, demonstrating 2D scaling with a high connectivity of such implementations remains a challenge.
NATURE NANOTECHNOLOGY
(2021)
Article
Chemistry, Physical
Arseny Kovyrshin, Marten Skogh, Lars Tornberg, Anders Broo, Stefano Mensa, Emre Sahin, Benjamin C. B. Symons, Jason Crain, Ivano Tavernelli
Summary: This article discusses the application of coupled quantum electron-nuclear dynamics in the Born-Huang expansion of the molecular wave function and the perturbation of nonadiabatic effects. Meanwhile, a quantum algorithm for simulating the time evolution of molecular systems is proposed and applied to the proton transfer dynamics in malonaldehyde. The proposed algorithm can be easily extended to include the dynamics of the classically described molecular scaffold. If the electrons do not adiabatically follow the nuclear displacement, the entanglement between electronic and nuclear degrees of freedom can persist for a long time. When powerful quantum computers become available, the proposed algorithm may become a valid candidate for studying such phenomena.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Tsumugi Miyashita, Paulina Jaimes, Tianquan Lian, Ming Lee Tang, Zihao Xu
Summary: The study investigates the impact of ligands on photon upconversion and finds that long-chain ligands decrease the efficiency of energy transfer, while short-chain ligands enable direct energy transfer and enhance the upconversion quantum yield.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Multidisciplinary Sciences
Runyu Lu, Kaipeng Liu, Yue Ban
Summary: This paper focuses on the robust control of a singlet-triplet qubit in a nanowire double quantum dot using inverse engineering and shortcuts to adiabaticity (STA). The optimization of STA with respect to systematic errors and the application of optimal control techniques are explored.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2022)
Article
Optics
G. J. Delben, M. W. Beims, M. G. E. da Luz
Summary: This paper discusses the difficulties and methods to overcome them in quantum control of a two-level system under the influence of both Markovian and non-Markovian noise. The results show that for Markovian noise, the breakdown time decreases with the decay rate ⠂ not as an exponential but as a power law, indicating that stronger coupling between the system and the environment allows for quantum control. Moreover, for non-Markovian noise, the breakdown time is longer when there is backflow, i.e., ⠂(t) can be negative. These results reveal favorable scenarios for operating qubits in a noisy medium.
Article
Optics
G. J. Delben, M. W. Beims, G. E. da Luz
Summary: This paper discusses the quantum control problem of a two-level system under the influence of both Markovian and non-Markovian noise, and proposes solutions such as employing a fast control scheme or controlling the off-diagonal terms of the system density matrix. The experimental results reveal that the breakdown time of quantum control is related to the coupling strength under Markovian noise, and is longer when there is backflow under non-Markovian noise.
Article
Physics, Applied
P. Pyshkin, A. Gabris, Da-Wei Luo, J. Q. You, Lian-Ao Wu
Summary: We propose and analyze a nonunitary variant of the continuous time Grover search algorithm based on frequent Zeno-type measurements. We show that the algorithm scales similarly to the pure quantum version by deriving tight analytical lower bounds on its efficiency for arbitrary database sizes and measurement parameters. We also study the behavior of the algorithm subject to noise, and find that under certain oracle and operational errors our measurement-based algorithm outperforms the standard algorithm, showing robustness against these noises. Our analysis is based on deriving a non-Hermitian effective description of the algorithm, which yields a deeper insight into components responsible for the quantum and the classical operation of the protocol.
PHYSICAL REVIEW APPLIED
(2022)
Article
Quantum Science & Technology
Tong Liu, Jin-Guo Liu, Heng Fan
Summary: Simulation of quantum materials is a significant application of quantum computers. Implementing nonunitary operations, which are widely used in classical approaches, on a quantum computer requires special design. By applying Grover's algorithm, a probabilistic method of implementing nonunitary operations can be extended to increase success probability without fidelity decreasing, and this method can be applied to problems such as imaginary time evolution and contraction of tensor networks on a quantum computer.
QUANTUM INFORMATION PROCESSING
(2021)
Article
Quantum Science & Technology
George Gillard, Ian M. Griffiths, Gautham Ragunathan, Ata Ulhaq, Callum McEwan, Edmund Clarke, Evgeny A. Chekhovich
Summary: By adjusting the tunneling coupling range, including the limit of isolated quantum dots, we unravel the contributions of spin relaxation mechanisms in quantum dot spins. The experimental results show that while reducing tunneling can extend the lifetime of electron spin qubits, it can also decrease the fidelity of optical spin initialization.
NPJ QUANTUM INFORMATION
(2021)
Article
Optics
Yusef Maleki, Sergei Sheludiakov, Vladimir V. Khmelenko, Marlan O. Scully, David M. Lee, Aleksei M. Zheltikov
Summary: The spectrum of the hydrogen atom is considered the key to unlocking the mysteries of quantum mechanics. In addition to being a basic model, the hydrogen atom also serves as a fundamental building block for quantum information. An external magnetic field can induce and sustain hyperfine-structure entanglement, enabling magnetic-field-assisted entanglement engineering at high temperatures.
Article
Multidisciplinary Sciences
Satyendra Nath Gupta, Ora Bitton, Tomas Neuman, Ruben Esteban, Lev Chuntonov, Javier Aizpurua, Gilad Haran
Summary: Plasmonic cavities can confine electromagnetic radiation to deep sub-wavelength regimes, allowing for strong coupling phenomena with individual quantum emitters. By studying scattering spectra and using interferometry, researchers observed Rabi splitting and non-classical emission in devices with semiconductor quantum dots, revealing complex interactions between bright and dark states. Model simulations based on an extended Jaynes-Cummings Hamiltonian explained the experimental findings, highlighting the potential of controlling quantum state dynamics through the coupling of quantum emitters to plasmonic cavities.
NATURE COMMUNICATIONS
(2021)
Article
Chemistry, Physical
HuiMin Ma, Joern Manz, HuiHui Wang, YiJing Yan, Yonggang Yang
Summary: We have developed a universal method to investigate ultrafast laser induced charge migration in molecules, encompassing both electronic and nuclear dynamics. This method is applicable to larger systems. A comprehensive analysis of charge migration in pyrene has been conducted, revealing and explaining the decoherences and recoherences in terms of nuclear motions.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Thomas Schnappinger, Regina de Vivie-Riedle
Summary: Researchers use ultrafast optical techniques to study molecular dynamics involving both nuclear and electronic motions, and theoretical approaches are needed for interpretation. They revisit and expand a coupled description method for simulating molecular dynamics and aim to control the system dynamics using laser pulses.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Marcel Meyer, Corentin Deprez, Timo R. van Abswoude, Ilja N. Meijer, Dingshan Liu, Chien-An Wang, Saurabh Karwal, Stefan Oosterhout, Francesco Borsoi, Amir Sammak, Nico W. Hendrickx, Giordano Scappucci, Menno Veldhorst
Summary: This article introduces a method of voltage adjustment using the gate voltage characteristics to achieve uniformity in the pinch-off voltages of quantum dots. The method is demonstrated to increase the stability of the quantum dots and offers new possibilities for scalable spin qubit arrays.
Article
Multidisciplinary Sciences
Ke Wang, Gang Xu, Fei Gao, He Liu, Rong-Long Ma, Xin Zhang, Zhanning Wang, Gang Cao, Ting Wang, Jian-Jun Zhang, Dimitrie Culcer, Xuedong Hu, Hong-Wen Jiang, Hai-Ou Li, Guang-Can Guo, Guo-Ping Guo
Summary: Hole-spin qubits in germanium show promise for rapid, all-electrical qubit control. The authors demonstrate ultrafast single-spin manipulation in a hole-based double quantum dot in a germanium hut wire, with a record Rabi frequency exceeding 540 MHz. These results suggest the potential for ultrafast coherent control of hole spin qubits to meet the requirements for scalable quantum information processing.
NATURE COMMUNICATIONS
(2022)
