Quantum gate
View article
Quantum Computing in the NISQ era and beyond Open
Noisy Intermediate-Scale Quantum (NISQ) technology will be available in the near future. Quantum computers with 50-100 qubits may be able to perform tasks which surpass the capabilities of today's classical digital computers, but noise in …
View article
Evaluating analytic gradients on quantum hardware Open
An important application for near-term quantum computing lies in optimization\ntasks, with applications ranging from quantum chemistry and drug discovery to\nmachine learning. In many settings --- most prominently in so-called\nparametrize…
View article
High-Fidelity Quantum Logic Gates Using Trapped-Ion Hyperfine Qubits Open
We demonstrate laser-driven two-qubit and single-qubit logic gates with respective fidelities 99.9(1)% and 99.9934(3)%, significantly above the ≈99% minimum threshold level required for fault-tolerant quantum computation, using qubits stor…
View article
Efficient gates for quantum computing Open
For superconducting qubits, microwave pulses drive rotations around the Bloch\nsphere. The phase of these drives can be used to generate zero-duration\narbitrary "virtual" Z-gates which, combined with two $X_{\\pi/2}$ gates, can\ngenerate …
View article
Resonantly driven CNOT gate for electron spins Open
Building an essential quantum component To build a universal quantum computer—the kind that can handle any computational task you throw at it—an essential early step is to demonstrate the so-called CNOT gate, which acts on two qubits. Zaja…
View article
Tackling the Qubit Mapping Problem for NISQ-Era Quantum Devices Open
Due to little consideration in the hardware constraints, e.g., limited connections between physical qubits to enable twoqubit gates, most quantum algorithms cannot be directly executed on the Noisy Intermediate-Scale Quantum (NISQ) devices…
View article
Procedure for systematically tuning up cross-talk in the cross-resonance gate Open
We present improvements in both theoretical understanding and experimental\nimplementation of the cross resonance (CR) gate that have led to shorter\ntwo-qubit gate times and interleaved randomized benchmarking fidelities\nexceeding 99%. T…
View article
Qudits and High-Dimensional Quantum Computing Open
Qudit is a multi-level computational unit alternative to the conventional\n2-level qubit. Compared to qubit, qudit provides a larger state space to store\nand process information, and thus can provide reduction of the circuit\ncomplexity, …
View article
Quantum advantage with shallow circuits Open
Quantum outperforms classical Quantum computers are expected to be better at solving certain computational problems than classical computers. This expectation is based on (well-founded) conjectures in computational complexity theory, but r…
View article
High-fidelity parallel entangling gates on a neutral-atom quantum computer Open
The ability to perform entangling quantum operations with low error rates in a scalable fashion is a central element of useful quantum information processing 1 . Neutral-atom arrays have recently emerged as a promising quantum computing pl…
View article
Tunable Coupling Scheme for Implementing High-Fidelity Two-Qubit Gates Open
The prospect of computational hardware with quantum advantage relies critically on the quality of quantum-gate operations. Imperfect two-qubit gates are a major bottleneck for achieving scalable quantum-information processors. Here, we pro…
View article
Open Quantum Assembly Language Open
This document describes a quantum assembly language (QASM) called OpenQASM that is used to implement experiments with low depth quantum circuits. OpenQASM represents universal physical circuits over the CNOT plus SU(2) basis with straight-…
View article
Improved Classical Simulation of Quantum Circuits Dominated by Clifford Gates Open
We present a new algorithm for classical simulation of quantum circuits over the Clifford+T gate set. The runtime of the algorithm is polynomial in the number of qubits and the number of Clifford gates in the circuit but exponential in the…
View article
Demonstration of universal parametric entangling gates on a multi-qubit lattice Open
Harnessing techniques from analog signal processing, we establish a new path for large-scale quantum computation.
View article
Scalable Gate Architecture for a One-Dimensional Array of Semiconductor Spin Qubits Open
We demonstrate a 12 quantum dot device fabricated on an undoped Si/SiGe heterostructure as a proof-of-concept for a scalable, linear gate architecture for semiconductor quantum dots. The device consists of 9 quantum dots in a linear array …
View article
A Race-Track Trapped-Ion Quantum Processor Open
We describe and benchmark a new quantum charge-coupled device (QCCD) trapped-ion quantum computer based on a linear trap with periodic boundary conditions, which resembles a race track. The new system successfully incorporates several tech…
View article
A programmable qudit-based quantum processor Open
Controlling and programming quantum devices to process quantum information by the unit of quantum dit, i.e., qudit, provides the possibilities for noise-resilient quantum communications, delicate quantum molecular simulations, and efficien…
View article
Complete 3-Qubit Grover search on a programmable quantum computer Open
The Grover quantum search algorithm is a hallmark application of a quantum computer with a well-known speedup over classical searches of an unsorted database. Here, we report results for a complete three-qubit Grover search algorithm using…
View article
High-Dimensional Single-Photon Quantum Gates: Concepts and Experiments Open
Transformations on quantum states form a basic building block of every quantum information system. From photonic polarization to two-level atoms, complete sets of quantum gates for a variety of qubit systems are well known. For multilevel …
View article
Toward large-scale fault-tolerant universal photonic quantum computing Open
Photonic quantum computing is one of the leading approaches to universal quantum computation. However, large-scale implementation of photonic quantum computing has been hindered by its intrinsic difficulties, such as probabilistic entangli…
View article
Automated optimization of large quantum circuits with continuous parameters Open
We develop and implement automated methods for optimizing quantum circuits of the size and type expected in quantum computations that outperform classical computers. We show how to handle continuous gate parameters and report a collection …
View article
Quantum circuits for isometries Open
We consider the decomposition of arbitrary isometries into a sequence of\nsingle-qubit and Controlled-NOT (C-NOT) gates. In many experimental\narchitectures, the C-NOT gate is relatively 'expensive' and hence we aim to\nkeep the number of …
View article
A quantum-logic gate between distant quantum-network modules Open
Quantum gating at a distance The processing of quantum information is reliant on the encoding and manipulation of quantum states of a qubit. Superconducting circuits are the most advanced platform at present, but there is an issue with cro…
View article
Adaptive quantum approximate optimization algorithm for solving combinatorial problems on a quantum computer Open
The quantum approximate optimization algorithm (QAOA) is a hybrid variational quantum-classical algorithm that solves combinatorial optimization problems. While there is evidence suggesting that the fixed form of the standard QAOA Ansatz i…
View article
Parametrically Activated Entangling Gates Using Transmon Qubits Open
We describe and implement a family of entangling gates activated by radio-frequency flux modulation applied to a tunable transmon that is statically coupled to a neighboring transmon. The effect of this modulation is the resonant exchange …
View article
High-Fidelity, High-Scalability Two-Qubit Gate Scheme for Superconducting Qubits Open
High-quality two-qubit gate operations are crucial for scalable quantum information processing. Often, the gate fidelity is compromised when the system becomes more integrated. Therefore, a low-error-rate, easy-to-scale two-qubit gate sche…
View article
Advantages of using relative-phase Toffoli gates with an application to multiple control Toffoli optimization Open
Various implementations of the Toffoli gate up to a relative phase have been known for years. The advantage over regular Toffoli gate is their smaller circuit size. However, their use has been often limited to a demonstration of quantum co…
View article
Electro-Optic Frequency Beam Splitters and Tritters for High-Fidelity Photonic Quantum Information Processing Open
We report the experimental realization of high-fidelity photonic quantum gates for frequency-encoded qubits and qutrits based on electro-optic modulation and Fourier-transform pulse shaping. Our frequency version of the Hadamard gate offer…
View article
Plug-and-Play Approach to Nonadiabatic Geometric Quantum Gates Open
Nonadiabatic holonomic quantum computation (NHQC) has been developed to shorten the construction times of geometric quantum gates. However, previous NHQC gates require the driving Hamiltonian to satisfy a set of rather restrictive conditio…
View article
Quantum Algorithms for Systems of Linear Equations Inspired by Adiabatic Quantum Computing Open
We present two quantum algorithms based on evolution randomization, a simple variant of adiabatic quantum computing, to prepare a quantum state |x⟩ that is proportional to the solution of the system of linear equations Ax[over →]=b[over →]…