Quantum Brain

Papers

Live trends in quantum computing research, updated daily from arXiv.

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27,749

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1,196

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13,032 papers in 12 months (-2% vs prior quarter)

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Papers by research theme (12 months). Hover for details.

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4,729 papers found

Measurement Crosstalk Errors in Cloud-Based Quantum Computing

Seungchan Seo, J. Bae·Dec 2, 2021

Quantum technologies available currently contain noise in general, often dubbed noisy intermediate-scale quantum systems. We here present the verification of noise in measurement readout errors in cloud-based quantum computing services, IBMQ and Rige...

Computer SciencePhysics

Best-Practice Aspects of Quantum-Computer Calculations: A Case Study of the Hydrogen Molecule

Ivana Miháliková, M. Friák, Matej Pivoluska +3 more·Dec 2, 2021

Quantum computers are reaching one crucial milestone after another. Motivated by their progress in quantum chemistry, we performed an extensive series of simulations of quantum-computer runs that were aimed at inspecting the best-practice aspects of ...

MedicinePhysics

EQC: ensembled quantum computing for variational quantum algorithms

S. Stein, Yufei Ding, N. Wiebe +5 more·Nov 29, 2021

Variational quantum algorithm (VQA), which is comprised of a classical optimizer and a parameterized quantum circuit, emerges as one of the most promising approaches for harvesting the power of quantum computers in the noisy intermediate scale quantu...

PhysicsComputer Science

Coupling the motional quantum states of spatially distant ions using a conducting wire

N. V. Horne, M. Mukherjee·Nov 29, 2021

Interfacing ion qubits in separate traps is among the challenges towards scaling up ion quantum computing. This theoretical study focuses on using a conducting wire to couple the motional quantum states of ions in separate planar traps. This approach...

Physics

Quantifying fermionic nonlinearity of quantum circuits

Shigeo Hakkaku, Yuichiro Tashima, K. Mitarai +2 more·Nov 29, 2021

Variational quantum algorithms (VQAs) have been proposed as one of the most promising approaches to demonstrate quantum advantage on noisy intermediate-scale quantum (NISQ) devices. However, it has been unclear whether VQAs can maintain quantum advan...

Physics

Quantum search degeneration under amplitude noise in queries to the oracle

A. Rastegin, A. M. Shemet·Nov 29, 2021

We examine how amplitude noise in queries to the oracle degrades a performance of quantum search algorithm. The Grover search and similar techniques are widely used in various quantum algorithms, including cases where rival parties are fighting over ...

Computer SciencePhysics

Random Quantum Circuits Transform Local Noise into Global White Noise

A. Dalzell, Nicholas Hunter-Jones, F. Brandão·Nov 29, 2021

We study the distribution over measurement outcomes of noisy random quantum circuits in the regime of low fidelity, which corresponds to the setting where the computation experiences at least one gate-level error with probability close to one. We mod...

Physics

Probing many-body localization by excited-state variational quantum eigensolver

Shuo Liu, Shi-Xin Zhang, Chang-Yu Hsieh +2 more·Nov 26, 2021

Non-equilibrium physics including many-body localization (MBL) has attracted increasing attentions, but theoretical approaches of reliably studying non-equilibrium properties remain quite limited. In this Letter, we propose a systematic approach to p...

Physics

Performance comparison of optimization methods on variational quantum algorithms

Xavier Bonet-Monroig, Hao Wang, D. Vermetten +5 more·Nov 26, 2021

Variational quantum algorithms (VQAs) offer a promising path toward using near-term quantum hardware for applications in academic and industrial research. These algorithms aim to find approximate solutions to quantum problems by optimizing a parametr...

Physics

Training a quantum measurement device to discriminate unknown non-orthogonal quantum states

D. Concha, L. Pereira, L. Zambrano +1 more·Nov 26, 2021

Here, we study the problem of decoding information transmitted through unknown quantum states. We assume that Alice encodes an alphabet into a set of orthogonal quantum states, which are then transmitted to Bob. However, the quantum channel that medi...

MedicinePhysics

Quantum Simulation of Molecules in Solution

D. Castaldo, S. Jahangiri, A. Delgado +1 more·Nov 26, 2021

Quantum chemical calculations on quantum computers have been focused mostly on simulating molecules in the gas phase. Molecules in liquid solution are, however, most relevant for chemistry. Continuum solvation models represent a good compromise betwe...

PhysicsMedicine

Towards Efficient Ansatz Architecture for Variational Quantum Algorithms

Anbang Wu, Gushu Li, Yuke Wang +3 more·Nov 26, 2021

Variational quantum algorithms are expected to demonstrate the advantage of quantum computing on near-term noisy quantum computers. However, training such variational quantum algorithms suffers from gradient vanishing as the size of the algorithm inc...

PhysicsComputer Science

Mitigating Noise-Induced Gradient Vanishing in Variational Quantum Algorithm Training

Anbang Wu, Gushu Li, Yufei Ding +1 more·Nov 25, 2021

Variational quantum algorithms are expected to demonstrate the advantage of quantum computing on near-term noisy quantum computers. However, training such variational quantum algorithms suffers from gradient vanishing as the size of the algorithm inc...

PhysicsComputer Science

Performance of Grover’s search algorithm with diagonalizable collective noises

Minghua Pan, Taiping Xiong, Shenggen Zheng·Nov 24, 2021

Grover’s search algorithm (GSA) is known to experience a loss of its quadratic speedup when exposed to quantum noise. In this study, we partially agree with this result and present our findings. First, we examine different typical diagonalizable nois...

PhysicsComputer Science

Demonstration of fault-tolerant universal quantum gate operations

L. Postler, Sascha Heußen, Ivan Pogorelov +10 more·Nov 24, 2021

Quantum computers can be protected from noise by encoding the logical quantum information redundantly into multiple qubits using error-correcting codes1,2. When manipulating the logical quantum states, it is imperative that errors caused by imperfect...

PhysicsMedicine

Simulating strongly interacting Hubbard chains with the variational Hamiltonian ansatz on a quantum computer

Baptiste Anselme Martin, P. Simon, M. Rančić·Nov 23, 2021

Hybrid quantum-classical algorithms have been proposed to circumvent noise limitations in quantum computers. Such algorithms delegate only a calculation of the expectation value to the quantum computer. Among them, the Variational Quantum Eigensolver...

Physics

Noise-reducing encoding strategies for spin chains

C. Keele, A. Kay·Nov 23, 2021

We present an encoding technique that reduces the effects of noise on quantum spin systems whose operation is driven by Hamiltonian evolution. This technique is widely applicable, being most relevant to the scenarios where there are insufficient qubi...

Physics

Dimensional Expressivity Analysis, best-approximation errors, and automated design of parametric quantum circuits

L. Funcke, T. Hartung, K. Jansen +3 more·Nov 22, 2021

The design of parametric quantum circuits (PQCs) for efficient use in variational quantum simulations (VQS) is subject to two competing factors. On one hand, the set of states that can be generated by the PQC has to be large enough to contain the sol...

Physics

Spin Relaxation in Quasi-1D GaAs Mesowires: Control via Electric Field and Aspect Ratio

S. Castelletto, ChanJu You, Deborah L. Gater +1 more·Nov 17, 2021

We report on the measurements of spin relaxation in GaAs quasi-onedimensional mesowires, relying on spin noise spectroscopy, thus adding to the existing body of spin relaxation studies in bulk, two-dimensional and zero dimensional systems. In additio...

Physics

Stochastic gradient line Bayesian optimization for efficient noise-robust optimization of parameterized quantum circuits

Shiro Tamiya, H. Yamasaki·Nov 15, 2021

Optimizing parameterized quantum circuits is a key routine in using near-term quantum devices. However, the existing algorithms for such optimization require an excessive number of quantum-measurement shots for estimating expectation values of observ...

PhysicsComputer ScienceMathematics
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