Article
Physics, Multidisciplinary
Holly N. Tinkey, Craig R. Clark, Brian C. Sawyer, Kenton R. Brown
Summary: In this study, we implemented a 2-qubit entangling interaction using a stationary, bichromatic optical beam within a surface-electrode Paul trap. We achieved a constant Doppler shift during the transport by fine temporal adjustment of the moving confinement potential. The interaction between the transported ions through the laser beam produced Bell states with fidelities comparable to those produced by stationary gates. This result demonstrates the feasibility of actively incorporating ion transport into quantum information entangling operations.
PHYSICAL REVIEW LETTERS
(2022)
Article
Quantum Science & Technology
Reinhold Blumel, Nikodem Grzesiak, Neal Pisenti, Kenneth Wright, Yunseong Nam
Summary: Researchers have proposed a linear method to construct entangling gates on trapped-ion quantum computers. This method does not require any search in the parameter space, can achieve power-optimal gates, and can be stabilized at an arbitrary order.
NPJ QUANTUM INFORMATION
(2021)
Article
Quantum Science & Technology
Kaizhao Wang, Jing-Fan Yu, Pengfei Wang, Chunyang Luan, Jing-Ning Zhang, Kihwan Kim
Summary: This study proposes and investigates methods to speed up entangling operations in a trapped ions system with high fidelity. Firstly, a scheme to increase the speed of a two-qubit gate without being limited by the trap frequency is found. Secondly, a fast gate scheme for entangling more than two qubits simultaneously is studied, using the method of applying multiple frequency components on laser beams. Moreover, the effect of large excitation of motional mode beyond the limit of Lamb-Dicke approximation is carefully studied.
QUANTUM SCIENCE AND TECHNOLOGY
(2022)
Article
Physics, Multidisciplinary
Filippo M. Gambetta, Chi Zhang, Markus Hennrich, Igor Lesanovsky, Weibin Li
Summary: Conical intersections between electronic potential energy surfaces are crucial for studying nonadiabatic processes in the excited states of large molecules. By utilizing trapped Rydberg ions, these conical intersections can be engineered and their dynamics simulated on larger length and timescales, providing a highly controllable system. The presence of a conical intersection affects both nuclear and electronic dynamics, resulting in the inhibition of nuclear motion, and these effects can be monitored in real time through spectroscopic measurements.
PHYSICAL REVIEW LETTERS
(2021)
Article
Optics
B. P. Ruzic, T. A. Barrick, J. D. Hunker, R. J. Law, B. K. McFarland, H. J. McGuinness, L. P. Parazzoli, J. D. Sterk, J. W. Van der Wall, D. Stick
Summary: In this paper, the impact of coherent motional excitation on the entangling-gate error in trapped-ion quantum computers is analyzed. The results show that a small amount of coherent displacement can erode gate performance, but this error can be suppressed by adjusting the relative phase or using Walsh modulation. Experimental data from transported ions is also used to analyze the impact of coherent displacement on gate error under realistic conditions.
Article
Optics
Brian C. Sawyer, Kenton R. Brown
Summary: The proposed optical scheme generates entanglement between co-trapped alkaline-earth atomic ions with low error rates and can be implemented with a wide range of laser wavelengths. It can also be extended to include multiple species of ions for multispecies entanglement. The key elements of this technique involve utilizing ground and metastable electronic states as qubit levels within the entangling gate.
Article
Physics, Multidisciplinary
Y. Mei, Y. Li, H. Nguyen, P. R. Berman, A. Kuzmich
Summary: Researchers have created a special two-level system in an ensemble of several hundred atoms and observed oscillations between the ground state and collective Rydberg state. They have also obtained the light shifts of the qubits using interference techniques and derived an effective two-level model that agrees well with their observations.
PHYSICAL REVIEW LETTERS
(2022)
Article
Multidisciplinary Sciences
Nicolas Zuber, Viraatt S. V. Anasuri, Moritz Berngruber, Yi-Quan Zou, Florian Meinert, Robert Loew, Tilman Pfau
Summary: Researchers have discovered a new type of molecular ion based on the interaction between the ionic charge and a flipping-induced dipole of a highly excited electron, called Rydberg atom. This molecular ion has a bond length of several micrometres. Using a high-resolution ion microscope, they have measured the vibrational spectrum and spatially resolved the bond length and angular alignment of the molecule. Due to the large bond length, the molecular dynamics are extremely slow.
Article
Physics, Multidisciplinary
Meng-Ru Yun, Shuming Cheng, L. -L Yan, Y. Jia, S. -L. Su
Summary: This study proposes an efficient protocol to realize multi-qubit entangling gates with high fidelity in Rydberg atoms. The scheme utilizes soft quantum control and off-resonant pulses to drive the atoms to the ground-state subspace through unconventional Rydberg pumping, ensuring insensitivity to decay effects. Additionally, the adoption of Gaussian temporal modulation improves the scheme's robustness against model uncertainty. Numerical simulations validate the effectiveness of the proposed scheme.
Article
Quantum Science & Technology
Lukas Gerster, Fernando Martinez-Garcia, Pavel Hrmo, Martin W. van Mourik, Benjamin Wilhelm, Davide Vodola, Markus Mueller, Rainer Blatt, Philipp Schindler, Thomas Monz
Summary: An efficient calibration protocol has been developed and characterized to automatically estimate and adjust experimental parameters of the widely used two-qubit Molmer-Sorensen entangling gate operation in a trapped-ion quantum information processor, leading to a significant speedup in gate calibration procedure.
Article
Quantum Science & Technology
Charles Fromonteil, Dolev Bluvstein, Hannes Pichler
Summary: We present a new family of protocols for entangling gates for neutral atom qubits using the Rydberg blockade mechanism. These protocols implement controlled-phase gates through a series of global laser pulses resonant with the Rydberg excitation frequency. We analyze the robustness of these protocols against calibration errors and laser intensity fluctuations, and demonstrate their robustness in various fidelity measures. Furthermore, we discuss adaptations of these protocols to ensure robustness against atomic-motion-induced Doppler shifts.
Article
Physics, Multidisciplinary
Shiqing Tang, Chong Yang, Dongxiao Li, Xiaoqiang Shao
Summary: In this study, a scheme for rapidly implementing a three-atom Rydberg CCZ gate via a single pulse is proposed, using the Rydberg blockade effect. This gate is successfully applied to quantum algorithms like the Deutsch-Jozsa algorithm and Grover search. The logical states of the gate are encoded to avoid spontaneous emission effects, and individual addressing of atoms is not required in this protocol.
Article
Optics
R. Tyler Sutherland, Qian Yu, Kristin M. Beck, Hartmut Haffner
Summary: In this work, analytic formulas are derived to determine the effect of error mechanisms on one-and two-qubit gates in trapped ions and electrons. The formulas consider driving field inhomogeneities, static motional frequency shifts, trap anharmonicities, field inhomogeneities, heating, and motional dephasing. The authors show that the formulas are sufficient for determining error budgets for high-fidelity gates, eliminating the need for numerical simulations in future projects.
Review
Physics, Multidisciplinary
Zhengyang Cai, Chun -Yang Luan, Lingfeng Ou, Hengchao Tu, Zihan Yin, Jing -Ning Zhang, Kihwan Kim
Summary: The trapped-ion system has long been a leading platform for practical quantum computation and simulation. Quantum gates with trapped ions are known for their high fidelity. Recent advancements have focused on developing sophisticated schemes for quantum gates, such as modulation techniques, to improve speed, robustness, and applicability to multiple qubits.
JOURNAL OF THE KOREAN PHYSICAL SOCIETY
(2023)
Article
Optics
Yucheng He, Jing-Xin Liu, F-Q Guo, L-L Yan, Ronghui Luo, Erjun Liang, S-L Su, M. Feng
Summary: The scheme proposed in this study combines Vitanov-style pulses and dressed-state-based shortcut to adiabaticity (STA) to achieve multiple-qubit quantum state transfer and quantum logic gate in Rydberg atoms. By using STA technology to reduce the population of Rydberg excited states, the scheme demonstrates robustness to spontaneous emission, while well-designed pulses help minimize control errors. The dressed-state method applied in the scheme allows for smoother quantum state transfer operations with high fidelity, and is faster than traditional shortcut to adiabaticity methods.
OPTICS COMMUNICATIONS
(2022)
Article
Engineering, Electrical & Electronic
Marti Gutierrez, Achintya Paradkar, David Hambraeus, Gerard Higgins, Witlef Wieczorek
Summary: Researchers demonstrate chip-based magnetic levitation of superconducting microparticles and successfully trap a 50 μm diameter SnPb microparticle using a chip-based magnetic trap. They simulate and fabricate a trap capable of levitating superconducting particles with diameters ranging from 0.5 μm to 200 μm, using stacked silicon chips patterned with multi-winding superconducting coils made of niobium.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2022)
Article
Physics, Multidisciplinary
Gerard Higgins, Shalina Salim, Chi Zhang, Harry Parke, Fabian Pokorny, Markus Hennrich
Summary: Interferometry pulse sequences applied to a trapped ion optical qubit have been used to minimize the stray electric field in a linear Paul trap with high precision. The methods allow for accurate determination and reduction of stray field strength beyond current levels, while also offering robustness against laser detuning and pulse errors. This technique has potential applications in clock synchronization protocols and offers significant enhancement through quantum metrology.
NEW JOURNAL OF PHYSICS
(2021)
Article
Physics, Atomic, Molecular & Chemical
Chi Zhang, Chaoqun Zhang, Lan Cheng, Timothy C. Steimle, Michael R. Tarbutt
Summary: In this study, we theoretically investigated the impact of 4f electron excited states on laser cooling of YbF molecules. We found that the presence of 4f hole states hinders laser cooling and leads to molecule loss. We also identified a leakage phenomenon outside of the cooling cycle, which affects the cooling efficiency.
JOURNAL OF MOLECULAR SPECTROSCOPY
(2022)
Article
Physics, Applied
Marti Gutierrez Latorre, Gerard Higgins, Achintya Paradkar, Thilo Bauch, Witlef Wieczorek
Summary: This work demonstrates the levitation of superconducting microparticles in a magnetic chip trap for quantum experiments. The center-of-mass motion of the particle is measured using a superconducting quantum interference device magnetometer. The frequency shifts dependent on the motional amplitude are characterized, and the nonlinearity and mode coupling of the trap potential are explained using finite-element modeling. This work paves the way for quantum experiments and ultra-sensitive inertial sensors with magnetically levitated superconducting microparticles.
PHYSICAL REVIEW APPLIED
(2023)
Article
Physics, Multidisciplinary
Arian Jadbabaie, Yuiki Takahashi, Nickolas H. Pilgram, Chandler J. Conn, Yi Zeng, Chi Zhang, Nicholas R. Hutzler
Summary: Polyatomic molecules are sensitive probes for exploring charge-parity violating and parity violating physics beyond the Standard Model. This study characterizes the fundamental bending vibration of (YbOH)-Yb-174 using high-resolution optical spectroscopy and provides essential information for the search of Beyond Standard Model physics in linear polyatomic molecules.
NEW JOURNAL OF PHYSICS
(2023)
Article
Physics, Multidisciplinary
J. Hofer, R. Gross, G. Higgins, H. Huebl, O. F. Kieler, R. Kleiner, D. Koelle, P. Schmidt, J. A. Slater, M. Trupke, K. Uhl, T. Weimann, W. Wieczorek, M. Aspelmeyer
Summary: This study reports the levitation of a superconducting lead-tin sphere in a static magnetic trap, with monitoring of its motion and demonstration of magnetic feedback control. The experiment has established a promising platform for testing quantum physics in high mass and long coherence times.
PHYSICAL REVIEW LETTERS
(2023)
Article
Optics
Murilo H. Oliveira, Gerard Higgins, Chi Zhang, Ana Predojevic, Markus Hennrich, Romain Bachelard, Celso J. Villas-Boas
Summary: We propose a scheme to generate steady-state entanglement in a two-qubit system dissipatively through interaction with a bosonic mode. By compensating the mode dissipation with a coherent pump field, the system is driven into a stationary entangled state. We also present a scheme allowing for adiabatic transfer of population to the desired entangled state. The dynamics leading to entanglement in these schemes can be understood using analogies with electromagnetically induced transparency and stimulated Raman adiabatic passage, respectively.
Article
Materials Science, Multidisciplinary
Andreas Poschl, Alisa Danilenko, Deividas Sabonis, Kaur Kristjuhan, Tyler Lindemann, Candice Thomas, Michael J. Manfra, Charles M. Marcus
Summary: The charge character of Andreev bound states (ABSs) in a three-terminal semiconductor-superconductor hybrid nanowire was measured using local and nonlocal tunneling spectroscopy. The ABSs exhibited distinct local and nonlocal conductance signatures, which changed with magnetic field and gate voltage. At high magnetic fields, the charge of ABSs oscillated around zero as a function of gate voltage, consistent with the total Bardeen-Cooper-Schrieffer charge of ABSs.
Article
Optics
Jose A. S. Lourenco, Gerard Higgins, Chi Zhang, Markus Hennrich, Tommaso Macri
Summary: In this study, we simulate the dissipative dynamics of a mesoscopic system with long-range interactions and discover rich PT phase diagrams. We propose a method to probe the PT symmetries of such systems through studying their dynamics. Furthermore, we present a feasible proposal for implementing non-Hermitian physics with PT symmetry in Rydberg systems.
Article
Materials Science, Multidisciplinary
Andreas Poschl, Alisa Danilenko, Deividas Sabonis, Kaur Kristjuhan, Tyler Lindemann, Candice Thomas, Michael J. Manfra, Charles M. Marcus
Summary: In this study, local and nonlocal signatures of the hybridization between a quantum dot state and an extended Andreev bound state in a gate-defined InAs nanowire with multiple side probes were investigated. The characteristic spectroscopic pattern resulting from the hybridization was observed both locally, in the probe with the quantum dot, and nonlocally, in the tunnel conductance of a remote probe. The nonlocal signatures revealed the extended nature of the Andreev bound state.
Article
Quantum Science & Technology
Chi Zhang, M. R. Tarbutt
Summary: An array of polar molecules interacting with Rydberg atoms is a promising hybrid system for scalable quantum computation, with high fidelity and little sensitivity to particle motional states. This system allows for two-qubit gates in a static array, rapid qubit initialization, and efficient readout without driving molecular transitions or moving the molecules.
Article
Physics, Multidisciplinary
Gerard Higgins, Chi Zhang, Fabian Pokorny, Harry Parke, Erik Jansson, Shalina Salim, Markus Hennrich
Summary: In this study, the response of an atomic ion to an electric quadrupole field to second and higher orders was observed, which is attributed to the ion's electric quadrupole polarizability and hyperpolarizabilities. A single Sr-88(+) ion confined in the electric fields of a Paul trap and excited to Rydberg states was probed, showing atomic energy level shifts and spectral sidebands due to quadrupolar trapping fields. Second-order perturbation calculations describe well the effects on Rydberg S-1/2 states, while full diagonalization of the Hamiltonian captures the stronger effects on Rydberg P-1/2 states.
PHYSICAL REVIEW RESEARCH
(2021)
Article
Optics
Fernando R. Cardoso, Daniel Z. Rossatto, Gabriel P. L. M. Fernandes, Gerard Higgins, Celso J. Villas-Boas
Summary: Superpositions of two-mode squeezed states are investigated for potential applications in quantum information processing and quantum sensing. These states exhibit properties such as mode statistics, entanglement degree, and symmetric peaks in phase space that can be used as pointers for quantum sensors to indicate displacement of oscillators.