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Quantum computation holds the promise of solving computational problems which are believed to be classically intractable. However, in practice, quantum devices are still limited by their relatively short coherence times and imperfect…

Quantum Physics · Physics 2023-12-22 Sagar Silva Pratapsi , Diogo Cruz

Semiconductor spin qubits demonstrated single-qubit gates with fidelities up to $99.9\%$ benchmarked in the single-qubit subspace. However, tomographic characterizations reveals non-negligible crosstalk errors in a larger space.…

Combining tensor network techniques with quantum autoregressive moving average models, we quantify the effects of time-correlated noise on quantum algorithms and predict their performance at scale. As a paradigmatic test case, we examine…

Quantum Physics · Physics 2026-03-06 Amit Jamadagni , Gregory Quiroz , Eugene Dumitrescu

Superconducting quantum devices are a leading technology for quantum computation, but they suffer from several challenges. Gate errors, coherence errors and a lack of connectivity all contribute to low fidelity results. In particular,…

In order to enter the era of utility, noisy intermediate-scale quantum (NISQ) devices need to enable long-range entanglement of large qubit chains. However, due to the limited connectivity of superconducting NISQ devices, long-range…

Quantum Physics · Physics 2024-04-30 Jean-Baptiste Waring , Christophe Pere , Sebastien Le Beux

An important aspect that strongly impacts the experimental feasibility of quantum circuits is the ratio of gate times and typical error time scales. Algorithms with circuit depths that significantly exceed the error time scales will result…

Quantum Physics · Physics 2024-08-29 Daniel Basilewitsch , Clemens Dlaska , Wolfgang Lechner

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…

Quantum Physics · Physics 2020-12-24 Yuan Xu , Ji Chu , Jiahao Yuan , Jiawei Qiu , Yuxuan Zhou , Libo Zhang , Xinsheng Tan , Yang Yu , Song Liu , Jian Li , Fei Yan , Dapeng Yu

Near-term quantum computing (QC) systems have limited qubit counts, high gate (instruction) error rates, and typically support a minimal instruction set having one type of two-qubit gate (2Q). To reduce program instruction counts and…

Quantum Physics · Physics 2021-06-30 Prakash Murali , Lingling Lao , Margaret Martonosi , Dan Browne

Bosonic cat qubits stabilized by two-photon driven dissipation benefit from exponential suppression of bit-flip errors and an extensive set of gates preserving this protection. These properties make them promising building blocks of a…

We introduce a simple, widely applicable formalism for designing "error-divisible" two qubit gates: a quantum gate set where fractional rotations have proportionally reduced error compared to the full entangling gate. In current noisy…

Quantum Physics · Physics 2021-10-25 David Rodriguez Perez , Paul Varosy , Ziqian Li , Tanay Roy , Eliot Kapit , David Schuster

Quantum random access memory (QRAM)--memory which stores classical data but allows queries to be performed in superposition--is required for the implementation of numerous quantum algorithms. While naive implementations of QRAM are highly…

Quantum Physics · Physics 2021-06-08 Connor T. Hann , Gideon Lee , S. M. Girvin , Liang Jiang

We study the effects of imperfections on the fidelity of the Toffoli gate recently realized in a circuit~QED setup using quantum control methods. The noise is introduced in the interqubits interactions. The coupling constants are no longer…

Quantum Physics · Physics 2016-08-03 J. Khatibi Moqadam , Renato Portugal , N. F. Svaiter , G. O. Corrêa

Running quantum programs is fraught with challenges on on today's noisy intermediate scale quantum (NISQ) devices. Many of these challenges originate from the error characteristics that stem from rapid decoherence and noise during…

Quantum Physics · Physics 2020-05-27 Ellis Wilson , Sudhakar Singh , Frank Mueller

We simulate the implementation of a T-gate, or $\frac{\pi}{8}$-gate, for a [7,1,3] encoded logical qubit in a non-equiprobable error environment. We demonstrate that the use of certain non-fault tolerant methods in the implementation may…

Quantum Physics · Physics 2015-06-15 Yaakov S. Weinstein

One of the key challenges in current Noisy Intermediate-Scale Quantum (NISQ) computers is to control a quantum system with high-fidelity quantum gates. There are many reasons a quantum gate can go wrong -- for superconducting transmon…

The development of robust architectures capable of large-scale fault-tolerant quantum computation should consider both their quantum error-correcting codes, and the underlying physical qubits upon which they are built, in tandem. Following…

Quantum Physics · Physics 2021-10-19 Andrew S. Darmawan , Benjamin J. Brown , Arne L. Grimsmo , David K. Tuckett , Shruti Puri

While the accuracy of qubit operations has been greatly improved in the last decade, further development is demanded to achieve the ultimate goal: a fault-tolerant quantum computer that can solve real-world problems more efficiently than…

Quantum Physics · Physics 2024-08-29 Kiyoto Nakamura , Joachim Ankerhold

Quantum advantage requires overcoming noise-induced degradation of quantum systems. Conventional methods for reducing noise such as error mitigation face scalability issues in deep circuits. Specifically, noise hampers the extraction of…

Quantum Physics · Physics 2023-12-05 Yonglong Ding , Ruyu Yang

We introduce entanglement purification protocols for d-level systems (qudits) with improved efficiency as compared to previous protocols. While we focus on protocols for bipartite systems, we also propose generalizations to multi-partite…

Quantum Physics · Physics 2018-10-17 Jorge Miguel-Ramiro , Wolfgang Dür

Quantum noise in real-world devices poses a significant challenge in achieving practical quantum advantage, since accurately compiled and executed circuits are typically deep and highly susceptible to decoherence. To facilitate the…

Quantum Physics · Physics 2025-06-13 Yuchen Guo , Shuo Yang