Quantum Brain

Papers

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

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28,891

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551

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13,849 papers in 12 months (-10% vs prior quarter)

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

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6,349 papers found

Efficient classical simulation of random shallow 2D quantum circuits

John Napp, R. L. Placa, A. Dalzell +2 more·Dec 31, 2019

Random quantum circuits are commonly viewed as hard to simulate classically. In some regimes this has been formally conjectured, and there had been no evidence against the more general possibility that for circuits with uniformly random gates, approx...

Computer SciencePhysics

Symmetry-adapted variational quantum eigensolver

K. Seki, T. Shirakawa, S. Yunoki·Dec 31, 2019

We propose a scheme to restore spatial symmetry of Hamiltonian in the variational-quantum-eigensolver (VQE) algorithm for which the quantum circuit structures used usually break the Hamiltonian symmetry. The symmetry-adapted VQE scheme introduced her...

Physics

What do QAOA energies reveal about graphs

M. Szegedy·Dec 27, 2019

Quantum Approximate Optimization Algorithm (QAOA) is a hybrid classical-quantum algorithm to approximately solve NP optimization problems such as MAX-CUT. We describe a new application area of QAOA circuits: graph structure discovery. We omit the tim...

PhysicsMathematics

Framework for simulating gauge theories with dipolar spin systems

Di Luo, Jiayu Shen, Michael Highman +4 more·Dec 24, 2019

Gauge theories appear broadly in physics, ranging from the standard model of particle physics to long-wavelength descriptions of topological systems in condensed matter. However, systems with sign problems are largely inaccessible to classical comput...

Physics

Destructive Error Interference in Product-Formula Lattice Simulation.

Minh C. Tran, Su-Kuan Chu, Yuan Su +2 more·Dec 23, 2019

Quantum computers can efficiently simulate the dynamics of quantum systems. In this Letter, we study the cost of digitally simulating the dynamics of several physically relevant systems using the first-order product-formula algorithm. We show that th...

PhysicsMedicine

Probabilistic simulation of quantum circuits using a deep-learning architecture

J. Carrasquilla, Di Luo, Felipe Pérez +4 more·Dec 23, 2019

The fundamental question of how to best simulate quantum systems using conventional computational resources lies at the forefront of condensed matter and quantum computation. It impacts both our understanding of quantum materials and our ability to e...

PhysicsComputer Science

Bayesian machine learning for Boltzmann machine in quantum-enhanced feature spaces

Yusen Wu, Chao-Hua Yu, S. Qin +2 more·Dec 20, 2019

Bayesian learning is ubiquitous for implementing classification and regression tasks, however, it is accompanied by computationally intractable limitations when the feature spaces become extremely large. Aiming to solve this problem, we develop a qua...

Computer SciencePhysics

Enhanced connectivity of quantum hardware with digital-analog control

Asier Galicia, Borja Ramon, E. Solano +1 more·Dec 19, 2019

Quantum computers based on superconducting circuits are experiencing a rapid development, aiming at outperforming classical computers in certain useful tasks in the near future. However, the currently available chip fabrication technologies limit the...

PhysicsComputer Science

Decoherence in Molecular Electron Spin Qubits: Insights from Quantum Many-Body Simulations.

Jia Chen, Cong Hu, J. Stanton +3 more·Dec 19, 2019

Quantum states are described by wave functions whose phases cannot be directly measured, but which play a vital role in quantum effects such as interference and entanglement. The loss of the relative phase information, termed decoherence, arises from...

MedicinePhysics

Quantum natural gradient generalized to noisy and nonunitary circuits

Bálint Koczor, S. Benjamin·Dec 18, 2019

Variational quantum algorithms are promising tools whose efficacy depends on their optimisation method. For noise-free unitary circuits, the quantum generalisation of natural gradient descent has been introduced and shown to be equivalent to imaginar...

Physics

Trapping Alkaline Earth Rydberg Atoms Optical Tweezer Arrays.

Jack Wilson, Samuel Saskin, Y. Meng +4 more·Dec 18, 2019

Neutral atom qubits with Rydberg-mediated interactions are a leading platform for developing large-scale coherent quantum systems. In the majority of experiments to date, the Rydberg states are not trapped by the same potential that confines ground s...

PhysicsMedicine

A Theory of Trotter Error

Andrew M. Childs, Yuan Su, Minh C. Tran +2 more·Dec 18, 2019

The Lie-Trotter formula, together with its higher-order generalizations, provides a direct approach to decomposing the exponential of a sum of operators. Despite significant effort, the error scaling of such product formulas remains poorly understood...

MathematicsComputer SciencePhysics

Driven-dissipative quantum mechanics on a lattice: Describing a fermionic reservoir with the master equation and simulating it on a quantum computer

L. Re, Brian Rost, A. Kemper +1 more·Dec 17, 2019

The driven-dissipative many-body problem remains one of the most challenging unsolved problems in quantum mechanics. The advent of quantum computers may provide a unique platform for efficiently simulating such driven-dissipative systems. But there a...

Physics

QuESTlink—Mathematica embiggened by a hardware-optimised quantum emulator

Tyson Jones, S. Benjamin·Dec 17, 2019

We introduce QuESTlink,pronounced ‘quest link’, an open-source Mathematicapackage which efficiently emulates quantum computers. By integratingwith the Quantum Exact Simulation Toolkit (QuEST), QuESTlink offers ahigh-level, expressive and usable inter...

Computer SciencePhysics

Variational Quantum Circuits for Quantum State Tomography

Yong Liu, Dongyang Wang, Shichuan Xue +9 more·Dec 16, 2019

Quantum state tomography is a key process in most quantum experiments. In this work, we employ quantum machine learning for state tomography. Given an unknown quantum state, it can be learned by maximizing the fidelity between the output of a variati...

PhysicsComputer Science

Scalable Bayesian Hamiltonian learning

T. Evans, R. Harper, S. Flammia·Dec 16, 2019

As the size of quantum devices continues to grow, the development of scalable methods to characterise and diagnose noise is becoming an increasingly important problem. Recent methods have shown how to efficiently estimate Hamiltonians in principle, b...

PhysicsMathematics

Quantum advantage from energy measurements of many-body quantum systems

Leonardo Novo, Juan Bermejo-Vega, R. Garc'ia-Patr'on·Dec 13, 2019

The problem of sampling outputs of quantum circuits has been proposed as a candidate for demonstrating a quantum computational advantage (sometimes referred to as quantum "supremacy"). In this work, we investigate whether quantum advantage demonstrat...

Computer SciencePhysics

Additive-error fine-grained quantum supremacy

T. Morimae, Suguru Tamaki·Dec 13, 2019

It is known that several sub-universal quantum computing models, such as the IQP model, the Boson sampling model, the one-clean qubit model, and the random circuit model, cannot be classically simulated in polynomial time under certain conjectures in...

MathematicsComputer SciencePhysics

On the equivalence between quantum and random walks on finite graphs

M. G. Andrade, F. Marquezino, Daniel R. Figueiredo·Dec 12, 2019

Quantum walks on graphs are ubiquitous in quantum computing finding a myriad of applications. Likewise, random walks on graphs are a fundamental building block for a large number of algorithms with diverse applications. While the relationship between...

Computer ScienceMathematicsPhysics

Dynamical structure factors of dynamical quantum simulators

M. L. Baez, M. Goihl, J. Haferkamp +3 more·Dec 12, 2019

Significance Quantum simulators promise to offer new insights into strongly correlated matter beyond what is accessible by means of classical computers. We propose dynamical quantum simulators (DQSs) as a method to simulate dynamical structure factor...

PhysicsMedicine
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