Two-qubit sweet spots for capacitively coupled exchange-only spin qubits
- URL: http://arxiv.org/abs/2103.15681v4
- Date: Mon, 23 Aug 2021 02:44:01 GMT
- Title: Two-qubit sweet spots for capacitively coupled exchange-only spin qubits
- Authors: MengKe Feng, Lin Htoo Zaw, Teck Seng Koh
- Abstract summary: We study capacitive coupling between two triple quantum dot spin qubits encoded in the $S = 1/2$, $S_z = -1/2$ decoherence-free subspace -- the exchange-only (EO) spin qubits.
We report exact gate sequences for CPHASE and CNOT gates, and demonstrate theoretically, the existence of multiple two-qubit sweet spots (2QSS) in the parameter space of capacitively coupled EO qubits.
- Score: 0.0
- License: http://creativecommons.org/licenses/by/4.0/
- Abstract: The implementation of high fidelity two-qubit gates is a bottleneck in the
progress towards universal quantum computation in semiconductor quantum dot
qubits. We study capacitive coupling between two triple quantum dot spin qubits
encoded in the $S = 1/2$, $S_z = -1/2$ decoherence-free subspace -- the
exchange-only (EO) spin qubits. We report exact gate sequences for CPHASE and
CNOT gates, and demonstrate theoretically, the existence of multiple two-qubit
sweet spots (2QSS) in the parameter space of capacitively coupled EO qubits.
Gate operations have the advantage of being all-electrical, but charge noise
that couple to electrical parameters of the qubits cause decoherence. Assuming
noise with a 1/f spectrum, two-qubit gate fidelities and times are calculated,
which provide useful information on the noise threshold necessary for
fault-tolerance. We study two-qubit gates at single and multiple parameter
2QSS. In particular, for two existing EO implementations -- the resonant
exchange (RX) and the always-on exchange-only (AEON) qubits -- we compare
two-qubit gate fidelities and times at positions in parameter space where the
2QSS are simultaneously single-qubit sweet spots (1QSS) for the RX and AEON.
These results provide a potential route to the realization of high fidelity
quantum computation.
Related papers
- A diverse set of two-qubit gates for spin qubits in semiconductor quantum dots [5.228819198411081]
We propose and verify a fast composite two-qubit gate scheme to extend the available two-qubit gate types.
Our gate scheme limits the parameter requirements of all essential two-qubit gates to a common JDeltaE_Z region.
With this versatile composite gate scheme, broad-spectrum two-qubit operations allow us to efficiently utilize the hardware and the underlying physics resources.
arXiv Detail & Related papers (2024-04-29T13:37:43Z) - Realization of two-qubit gates and multi-body entanglement states in an asymmetric superconducting circuits [3.9488862168263412]
We propose a tunable fluxonium-transmon-transmon (FTT) cou pling scheme.
The asymmetric structure composed of fluxonium and transmon will optimize the frequency space and form a high fidelity two-qubit quantum gate.
We study the performance of this scheme by simulating the general single-qubit Xpi/2 gate and two-qubit (iSWAP) gate.
arXiv Detail & Related papers (2024-04-12T08:44:21Z) - QuantumSEA: In-Time Sparse Exploration for Noise Adaptive Quantum
Circuits [82.50620782471485]
QuantumSEA is an in-time sparse exploration for noise-adaptive quantum circuits.
It aims to achieve two key objectives: (1) implicit circuits capacity during training and (2) noise robustness.
Our method establishes state-of-the-art results with only half the number of quantum gates and 2x time saving of circuit executions.
arXiv Detail & Related papers (2024-01-10T22:33:00Z) - A SWAP Gate for Spin Qubits in Silicon [5.6151418663848744]
We show a fast SWAP gate with a duration of 25 ns based on quantum dots in isotopically enriched silicon.
We calibrate the single-qubit local phases during the SWAP gate by incorporating single-qubit gates in our circuit.
These results pave the way for high fidelity SWAP gates, and processes based on them, such as quantum communication on chip and quantum simulation.
arXiv Detail & Related papers (2023-10-10T15:24:15Z) - A vertical gate-defined double quantum dot in a strained germanium
double quantum well [48.7576911714538]
Gate-defined quantum dots in silicon-germanium heterostructures have become a compelling platform for quantum computation and simulation.
We demonstrate the operation of a gate-defined vertical double quantum dot in a strained germanium double quantum well.
We discuss challenges and opportunities and outline potential applications in quantum computing and quantum simulation.
arXiv Detail & Related papers (2023-05-23T13:42:36Z) - Cat-qubit-inspired gate on cos($2\theta$) qubits [77.34726150561087]
We introduce a single-qubit $Z$ gate inspired by the noise-bias preserving gate of the Kerr-cat qubit.
This scheme relies on a $pi$ rotation in phase space via a beamsplitter-like transformation between a qubit and ancilla qubit.
arXiv Detail & Related papers (2023-04-04T23:06:22Z) - Two qubits in one transmon -- QEC without ancilla hardware [68.8204255655161]
We show that it is theoretically possible to use higher energy levels for storing and controlling two qubits within a superconducting transmon.
The additional qubits could be used in algorithms which need many short-living qubits in error correction or by embedding effecitve higher connectivity in qubit networks.
arXiv Detail & Related papers (2023-02-28T16:18:00Z) - Universal qudit gate synthesis for transmons [44.22241766275732]
We design a superconducting qudit-based quantum processor.
We propose a universal gate set featuring a two-qudit cross-resonance entangling gate.
We numerically demonstrate the synthesis of $rm SU(16)$ gates for noisy quantum hardware.
arXiv Detail & Related papers (2022-12-08T18:59:53Z) - Modelling semiconductor spin qubits and their charge noise environment
for quantum gate fidelity estimation [0.9406493726662083]
The spin of an electron confined in semiconductor quantum dots is a promising candidate for quantum bit (qubit) implementations.
We present here a co-modelling framework for double quantum dot (DQD) devices and their charge noise environment.
We find an inverse correlation between quantum gate errors and quantum dot confinement.
arXiv Detail & Related papers (2022-10-10T10:12:54Z) - Benchmarking the noise sensitivity of different parametric two-qubit
gates in a single superconducting quantum computing platform [0.0]
A larger hardware-native gate set may decrease the number of required gates, provided that all gates are realized with high fidelity.
We benchmark both controlled-Z (CZ) and exchange-type (iSWAP) gates using a parametrically driven tunable coupler.
We argue that spurious $ZZ$-type couplings are the dominant error source for the iSWAP gate.
arXiv Detail & Related papers (2020-05-12T11:38:41Z) - 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.