Fractional Control Gate Protocols For Quantum Engines

• URL: http://arxiv.org/abs/2509.23997v1
• Date: Sun, 28 Sep 2025 17:42:42 GMT
• Title: Fractional Control Gate Protocols For Quantum Engines
• Authors: Elliot John Fox, Taysa Mendes de Mendonça, Ferdinand Schmidt-Kaler, Irene D'Amico,
• Abstract summary: Nth-root gates allow for a paced application of two-qubit operations.<n>We apply them in quantum thermodynamic protocols for operating a quantum heat engine.
• Score: 27.206151252240954
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: Nth-root gates allow for a paced application of two-qubit operations. We apply them in quantum thermodynamic protocols for operating a quantum heat engine. A set of circuits for two and three qubits are compared by considering maximum work production and related efficiency. Our results show that for all circuits considered and most regions of initial parameter space, quantum coherence of one of the qubits strongly increases the maximum work production and improves the system's performance as a quantum heat engine. In such circuits, coherence is initially imprinted into one of the qubits, improving the overall maximum extractable work. Work gets generated with 84% to 100% efficiency. Further, we uncover a strong linear correlation between work production and many-body correlations in the working medium generated by these gates.

Related papers

• Above 99.9% Fidelity Single-Qubit Gates, Two-Qubit Gates, and Readout in a Single Superconducting Quantum Device [58.154405222706146]
  tuning of qubit-coupler coupling strengths in a superconducting circuit with two transmon qubits coupled via a tunable coupler enables high-fidelity single- and two-qubit gates.<n>We achieve a 40h-averaged CZ gate fidelity of 99.93%, simultaneous single-qubit gate fidelities of 99.98%, and readout fidelities over 99.94% in a single device.
  arXiv  Detail & Related papers  (2025-08-22T14:49:47Z)
• Efficiency Enhancement up to Unity in a Generalized Quantum Otto Engine: Comparative Analysis with Conventional Quantum Otto Engine Utilizing a Two-Qubit Heisenberg XXZ Chain [0.0]
  A novel generalized quantum Otto cycle (GQOC) is introduced, featuring two distinct coupling configurations to thermal reservoirs.<n>The GQOC exhibits the potential for 100% efficiency, surpassing the efficiency of the conventional quantum Otto cycle.
  arXiv  Detail & Related papers  (2025-03-27T15:07:12Z)
• A Superconducting Qubit-Resonator Quantum Processor with Effective All-to-All Connectivity [44.72199649564072]
  This architecture can be used as a test-bed for algorithms that benefit from high connectivity.<n>We show that the central resonator can be used as a computational element.<n>We achieve a genuinely multi-qubit entangled Greenberger-Horne-Zeilinger (GHZ) state over all six qubits with a readout-error mitigated fidelity of $0.86$.
  arXiv  Detail & Related papers  (2025-03-13T21:36:18Z)
• Harnessing Nth Root Gates for Energy Storage [30.733286944793527]
  We explore the use of fractional control-not gates in quantum thermodynamics. Nth-root gate allows for a paced application of two-qubit operations. We apply it in quantum thermodynamic protocols for charging a quantum battery.
  arXiv  Detail & Related papers  (2024-09-16T14:57:55Z)
• Optimal control in large open quantum systems: the case of transmon readout and reset [44.99833362998488]
  We present a framework that combines the adjoint-state method together with reverse-time backpropagation to solve prohibitively large open-system quantum control problems.<n>We apply this framework to optimize two inherently dissipative operations in superconducting qubits.<n>Our results show that while standard pulses for dispersive readout are nearly optimal, adding a transmon drive during the protocol can yield 2x improvements in fidelity and duration.
  arXiv  Detail & Related papers  (2024-03-21T18:12:51Z)
• Variational-quantum-eigensolver-inspired optimization for spin-chain work extraction [39.58317527488534]
  Energy extraction from quantum sources is a key task to develop new quantum devices such as quantum batteries. One of the main issues to fully extract energy from the quantum source is the assumption that any unitary operation can be done on the system. We propose an approach to optimize the extractable energy inspired by the variational quantum eigensolver (VQE) algorithm.
  arXiv  Detail & Related papers  (2023-10-11T15:59:54Z)
• Direct pulse-level compilation of arbitrary quantum logic gates on superconducting qutrits [36.30869856057226]
  We demonstrate any arbitrary qubit and qutrit gate can be realized with high-fidelity, which can significantly reduce the length of a gate sequence. We show that optimal control gates are robust to drift for at least three hours and that the same calibration parameters can be used for all implemented gates.
  arXiv  Detail & Related papers  (2023-03-07T22:15:43Z)
• Experimental Realization of Two Qutrits Gate with Tunable Coupling in Superconducting Circuits [11.881366909450376]
  Gate-based quantum computation has been extensively investigated using quantum circuits based on qubits. One of the essential elements for qutrit-based quantum computation, two-qutrit quantum gate, remains a major challenge. We propose and demonstrate a highly efficient and scalable two-qutrit quantum gate in superconducting quantum circuits.
  arXiv  Detail & Related papers  (2022-06-22T16:33:58Z)
• Implementing two-qubit gates at the quantum speed limit [33.51056531486263]
  We experimentally demonstrate commonly used two-qubit gates at nearly the fastest possible speed. We achieve this quantum speed limit by implementing experimental gates designed using a machine learning inspired optimal control method. We expect our method to offer significant speedups for non-native two-qubit gates.
  arXiv  Detail & Related papers  (2022-06-15T18:00:00Z)
• Effective non-local parity-dependent couplings in qubit chains [0.0]
  We harness the simultaneous coupling of qubits on a chain and engineer a set of non-local parity-dependent quantum operations. The resulting effective long-range couplings directly implement a parametrizable Trotter-step for Jordan-Wigner fermions. We present numerical simulations of the gate operation in a superconducting quantum circuit architecture.
  arXiv  Detail & Related papers  (2022-03-14T17:33:40Z)
• Realization of arbitrary doubly-controlled quantum phase gates [62.997667081978825]
  We introduce a high-fidelity gate set inspired by a proposal for near-term quantum advantage in optimization problems. By orchestrating coherent, multi-level control over three transmon qutrits, we synthesize a family of deterministic, continuous-angle quantum phase gates acting in the natural three-qubit computational basis.
  arXiv  Detail & Related papers  (2021-08-03T17:49:09Z)
• Improving the Performance of Deep Quantum Optimization Algorithms with Continuous Gate Sets [47.00474212574662]
  Variational quantum algorithms are believed to be promising for solving computationally hard problems. In this paper, we experimentally investigate the circuit-depth-dependent performance of QAOA applied to exact-cover problem instances. Our results demonstrate that the use of continuous gate sets may be a key component in extending the impact of near-term quantum computers.
  arXiv  Detail & Related papers  (2020-05-11T17:20:51Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.