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ردیف | عنوان | نوع |
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1 |
Dual-Frequency Quantum Phase Estimation Mitigates the Spectral Leakage of Quantum Algorithms
تخمین فاز کوانتومی دو فرکانس برای کاهش نشت طیفی الگوریتمهای کوانتومی-2022 Quantum phase estimation is an important component in diverse quantum algorithms. However, it suffers from
spectral leakage, when the reciprocal of the record length is not an
integer multiple of the unknown phase, which incurs an accuracy
degradation. For the existing single-sample estimation scheme,
window-based methods have been proposed for spectral leakage
mitigation. As a further advance, we propose a dual-frequency estimator, which asymptotically approaches the Cramér-Rao bound,
when multiple samples are available. Numerical results show that
the proposed estimator outperforms the existing window-based
methods, when the number of samples is sufficiently high.
Index Terms: Algorithmic error mitigation | dual-frequency estimator | quantum algorithms | quantum phase estimation. |
مقاله انگلیسی |
2 |
Effects of Dynamical Decoupling and Pulse-Level Optimizations on IBM Quantum Computers
اثرات جداسازی دینامیکی و بهینه سازی سطح پالس بر روی کامپیوترهای کوانتومی IBM-2022 Currently available quantum computers are prone to errors. Circuit optimization and error
mitigation methods are needed to design quantum circuits to achieve better fidelity when executed on NISQ
hardware. Dynamical decoupling (DD) is generally used to suppress the decoherence error, and different DD
strategies have been proposed. Moreover, the circuit fidelity can be improved by pulse-level optimization,
such as creating hardware-native pulse-efficient gates. This article implements all the popular DD sequences
and evaluates their performances on IBM quantum chips with different characteristics for various wellknown quantum applications. Also, we investigate combining DD with the pulse-level optimization method
and apply them to QAOA to solve the max-cut problem. Based on the experimental results, we find that DD
can be a benefit for only certain types of quantum algorithms, while the combination of DD and pulse-level
optimization methods always has a positive impact. Finally, we provide several guidelines for users to learn
how to use these noise mitigation methods to build circuits for quantum applications with high fidelity on
IBM quantum computers.
INDEX TERMS: Error mitigation | noisy intermediate-scale quantum (NISQ) hardware. |
مقاله انگلیسی |
3 |
Enabling Pulse-Level Programming, Compilation, and Execution in XACC
فعال کردن برنامه نویسی، کامپایل و اجرا در سطح پالس در XACC-2022 Noisy gate-model quantum processing units (QPUs) are currently available from vendors over the cloud, and digital
quantum programming approaches exist to run low-depth circuits on physical hardware. These digital representations are ultimately
lowered to pulse-level instructions by vendor quantum control systems to affect unitary evolution representative of the submitted digital
circuit. Vendors are beginning to open this pulse-level control system to the public via specified interfaces. Robust programming
methodologies, software frameworks, and backend simulation technologies for this analog model of quantum computation will prove
critical to advancing pulse-level control research and development. Prototypical use cases for this include error mitigation, optimal
pulse control, and physics-inspired pulse construction. Here we present an extension to the XACC quantum-classical software
framework that enables pulse-level programming for superconducting, gate-model quantum computers, and a novel, general, and
extensible pulse-level simulation backend for XACC that scales on classical compute clusters via MPI. Our work enables custom
backend Hamiltonian definitions and gate-level compilation to available pulses with a focus on performance and scalability. We end with
a demonstration of this capability, and show how to use XACC for pertinent pulse-level programming tasks.
Index Terms: Quantum computing | quantum programming models | quantum control | quantum simulation |
مقاله انگلیسی |
4 |
Pauli Error Propagation-Based Gate Rescheduling for Quantum Circuit Error Mitigation
برنامه ریزی مجدد گیت مبتنی بر انتشار خطا پاولی برای کاهش خطای مدار کوانتومی-2022 Noisy intermediate-scale quantum algorithms, which run on noisy quantum computers, should
be carefully designed to boost the output state fidelity. While several compilation approaches have been
proposed to minimize circuit errors, they often omit the detailed circuit structure information that does
not affect the circuit depth or the gate count. In the presence of spatial variation in the error rate of the
quantum gates, adjusting the circuit structure can play a major role in mitigating errors. In this article, we
exploit the freedom of gate reordering based on the commutation rules to show the impact of gate error
propagation paths on the output state fidelity of the quantum circuit, propose advanced predictive techniques
to project the success rate of the circuit, and develop a new compilation phase postquantum circuit mapping
to improve its reliability. Our proposed approaches have been validated using a variety of quantum circuits
with different success metrics, which are executed on IBM quantum computers. Our results show that
rescheduling quantum gates based on their error propagation paths can significantly improve the fidelity
of the quantum circuit in the presence of variable gate error rates.
INDEX TERMS: Commutation rules | error propagation | gate rescheduling | noisy intermediate-scale quantum (NISQ) computer | Pauli errors | quantum circuit | quantum circuit mapping | reliability. |
مقاله انگلیسی |
5 |
Quantum Error Mitigation Relying on Permutation Filtering
کاهش خطای کوانتومی با تکیه بر فیلتر جایگشت-2022 Quantum error mitigation (QEM) is a class of
promising techniques capable of reducing the computational
error of variational quantum algorithms tailored for current
noisy intermediate-scale quantum computers. The recently pro-
posed permutation-based methods are practically attractive,
since they do not rely on any a priori information concerning
the quantum channels. In this treatise, we propose a general
framework termed as permutation filters, which includes the
existing permutation-based methods as special cases. In particular, we show that
the proposed filter design algorithm
always converge to the global optimum, and that the optimal
filters can provide substantial improvements over the existing
permutation-based methods in the presence of narrowband
quantum noise, corresponding to large-depth, high-error-rate
quantum circuits. keywords: Quantum error mitigation | permutation filtering | permutation symmetry | variational quantum algorithms. |
مقاله انگلیسی |
6 |
Testing Scalable Bell Inequalities for Quantum Graph States on IBM Quantum Devices
آزمایش نابرابری های بل مقیاس پذیر برای حالت های نمودار کوانتومی در دستگاه های کوانتومی IBM-2022 Testing and verifying imperfect multi-qubit
quantum devices are important as such noisy quantum devices
are widely available today. Bell inequalities are known to be
useful for testing and verifying the quality of the quantum devices
from their nonlocal quantum states and local measurements.
There have been many experiments demonstrating the violations
of Bell inequalities, but they are limited in the number of qubits
and the types of quantum states. We report violations of Bell
inequalities on IBM Quantum devices based on the scalable
and robust inequalities maximally violated by graph states as
proposed by Baccari et al.. The violations are obtained from
the quantum states of path graphs up to 57 and 21 qubits
on a 65-qubit and two 27-qubit IBM Quantum devices,
respectively, and from those of star graphs up to 11 qubits
with quantum readout error mitigation (QREM). We are able
to show violations of the inequalities on various graph states
by constructing low-depth quantum circuits and by applying
the QREM technique. We also point out that quantum circuits
for star graph states of size N can be realized with circuits
of depth O(√N) on subdivided honeycomb lattices which
are the topology of the 65-qubit IBM Quantum device. Our
experiments show encouraging results on the ability of existing
quantum devices to prepare entangled quantum states and
provide experimental evidence on the benefit of scalable Bell
inequalities for testing them.
Index Terms—Quantum computing | IBM quantum | benchmarking | graph state | bell inequality. |
مقاله انگلیسی |
7 |
The Accuracy vs: Sampling Overhead Trade-off in Quantum Error Mitigation Using Monte Carlo-Based Channel Inversion
دقت در مقابل نمونهبرداری سربار مبادله در کاهش خطای کوانتومی با استفاده از وارونگی کانال مبتنی بر مونت کارلو-2022 Quantum error mitigation (QEM) is a class of
promising techniques for reducing the computational error of
variational quantum algorithms. In general, the computational
error reduction comes at the cost of a sampling overhead due to
the variance-boosting effect caused by the channel inversion operation, which ultimately limits the applicability of QEM. Existing
sampling overhead analysis of QEM typically assumes exact
channel inversion, which is unrealistic in practical scenarios.
In this treatise, we consider a practical channel inversion strategy
based on Monte Carlo sampling, which introduces additional
computational error that in turn may be eliminated at the cost
of an extra sampling overhead. In particular, we show that when
the computational error is small compared to the dynamic range
of the error-free results, it scales with the square root of the
number of gates. By contrast, the error exhibits a linear scaling
with the number of gates in the absence of QEM under the
same assumptions. Hence, the error scaling of QEM remains to
be preferable even without the extra sampling overhead. Our
analytical results are accompanied by numerical examples.
Index Terms—Quantum error mitigation (QEM), Monte Carlo sampling, sampling overhead, error scaling behaviour. |
مقاله انگلیسی |
8 |
A Divide-and-Conquer Approach to Dicke State Preparation
رویکرد تفرقه بینداز و حکومت کن برای آماده سازی ایالت دیک-2022 We present a divide-and-conquer approach to deterministically prepare Dicke states |Dn k (i.e.,
equal-weight superpositions of all n-qubit states with Hamming weight k) on quantum computers. In an
experimental evaluation for up to n = 6 qubits on IBM Quantum Sydney and Montreal devices, we achieve
significantly higher state fidelity compared to previous results. The fidelity gains are achieved through several
techniques: our circuits first “divide” the Hamming weight between blocks of n/2 qubits, and then “conquer”
those blocks with improved versions of Dicke state unitaries (Bärtschi et al. FCT’2019). Due to the sparse
connectivity on IBM’s heavy-hex-architectures, these circuits are implemented for linear nearest neighbor
topologies. Further gains in (estimating) the state fidelity are due to our use of measurement error mitigation
and hardware progress.
keywords: Circuit | Dicke state | fidelity | IBM Q | noisy intermediate scale quantum (NISQ) | QISKIT | quantum computing | transpiler. |
مقاله انگلیسی |
9 |
Data-Driven Reliability Models of Quantum Circuit: From Traditional ML to Graph Neural Network
مدلهای قابلیت اطمینان مدار کوانتومی مبتنی بر داده: از ML سنتی تا شبکه عصبی نمودار-2022 The current advancement in quantum computers
has been focusing on increasing the number of qubits and
enhancing their fidelity. However, the available quantum devices,
known as Intermediate Scale Quantum (NISQ) computers, still
suffer from different sources of noise that impact their reliability.
Thus, practical noise modeling is of great importance in the
development of quantum error mitigation approaches.
In this paper, we propose a Machine Learning (ML)-based
scheme to predict the output fidelity of the quantum circuit
executed on NISQ devices. We show the benefit of using Graph
Neural Network (GNN)-based models compared to traditional
ML-based models in capturing the quantum circuit structure
in addition to its gates’ features, which enable characterizing
unpredicted quantum circuit errors. We use different metrics to
measure the fidelity of the quantum circuit output. Our experimental results using different quantum algorithms executed on
IBM Q Guadalupe quantum computer show the high prediction
accuracy of our ML reliability models. Our results also show
that our models can guide the single-qubit gate rescheduling to
improve the output fidelity of the quantum circuit without the
need for prior execution of dedicated calibration circuits.
Index Terms: Quantum computing | Quantum circuit | Machine learning | Reliability | Graph Neural Network (GNN) | Noisy Intermediate-Scale Quantum (NISQ) computer | Errors. |
مقاله انگلیسی |
10 |
Wood supply chain risks and risk mitigation strategies: A systematic review focusing on the Northern hemisphere
خطرات زنجیره تامین چوب و استراتژی های کاهش خطر: یک مرور سیستماتیک با تمرکز بر نیمکره شمالی-2021 This paper presents a systematic literature review on both the risks affecting wood supply security and risk mitigation strategies by quantitative and qualitative data analysis. It describes wood-specific supply chain risks, thereupon resulting impacts and counteracting strategies to ensure supply. Risks, impacts, and strategies are documented as basis for a comparative analysis, discussion of results, challenges and research gaps. Finally, the suitability and the limitations of the chosen methodology and the achieved results are discussed. Scanning wood supply chain risks and supply strategies, most of the reviewed papers focus on wood supply for bioenergy generation and only a few studies investigate wood supply chain risk issues for the sawing, wood panel, pulp and paper industries, or biorefineries.This review differs significantly from other reviews in this field as it considers the entire wood value chain including recent studies on new chemical wood-based products and thus provides a more complete picture of the wood-based bioeconomy. Consequently, it contributes to the literature by providing an overarching investigation of the risks affecting wood supply security and possible side effects of a growing wood-based bioeconomy. It was found that comprehensive value chain analyses considering established wood products, large-volume bioenergy products, as well as established and new chemical wood-based products in the context of wood supply security are missing. Studies that map the entire wood value chain with its multilevel interdependences and integrating cascading use of wood are lacking. Keywords: Wood supply | Wood supply chain risk | Supply risk mitigation | Wood supply strategy | Wood-based bioeconomy |
مقاله انگلیسی |