Quantum Brain

Papers

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

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31,611

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65

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15,669 papers in 12 months (-39% vs prior quarter)

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31,611 papers found

Near- and long-term quantum algorithmic approaches for vibrational spectroscopy

Nicolas P. D. Sawaya, F. Paesani, Daniel P. Tabor·Sep 10, 2020

Determining the vibrational structure of a molecule is central to fundamental applications in several areas, from atmospheric science to catalysis, fuel combustion modeling, biochemical imaging, and astrochemistry. However, when significant anharmoni...

Physics

Experimental authentication of quantum key distribution with post-quantum cryptography

Liu-Jun Wang, Kaiyi Zhang, Jia-Yong Wang +9 more·Sep 10, 2020

Quantum key distribution (QKD) can provide information theoretically secure key exchange even in the era of quantum computers. However, QKD requires the classical channel to be authenticated, the current method for which is pre-sharing symmetric keys...

Computer SciencePhysics

Advanced unembedding techniques for quantum annealers

Elijah Pelofske, Georg Hahn, H. Djidjev·Sep 10, 2020

The D-Wave quantum annealers make it possible to obtain high quality solutions of NP-hard problems by mapping a problem in a QUBO (quadratic unconstrained binary optimization) or Ising form to the physical qubit connectivity structure on the D-Wave c...

PhysicsComputer Science

Studying many-body localization in exchange-coupled electron spin qubits using spin-spin correlations

R. Throckmorton, S. Das Sarma·Sep 9, 2020

We show that many-body localization (MBL) effects can be observed in a finite chain of exchange-coupled spin qubits in the presence of both exchange and magnetic noise, a system that has been experimentally realized in semiconductors and is a potenti...

Physics

Breaking adiabatic quantum control with deep learning

Yongcheng Ding, Y. Ban, J. D. Mart'in-Guerrero +3 more·Sep 9, 2020

In the era of digital quantum computing, optimal digitized pulses are requisite for efficient quantum control. This goal is translated into dynamic programming, in which a deep reinforcement learning (DRL) agent is gifted. As a reference, shortcuts t...

PhysicsComputer Science

Rodeo Algorithm for Quantum Computing.

Kenneth Choi, Dean Lee, J. Bonitati +2 more·Sep 9, 2020

We present a stochastic quantum computing algorithm that can prepare any eigenvector of a quantum Hamiltonian within a selected energy interval [E-ε,E+ε]. In order to reduce the spectral weight of all other eigenvectors by a suppression factor δ, the...

PhysicsMedicine

Variational Preparation of the Sachdev-Ye-Kitaev Thermofield Double

V. P. Su·Sep 9, 2020

We provide an algorithm for preparing the thermofield double (TFD) state of the Sachdev-Ye-Kitaev model without the need for an auxiliary bath. Following previous work, the TFD can be cast as the approximate ground state of a Hamiltonian, $H_{\text{T...

Computer SciencePhysics

A four-qubit germanium quantum processor

N. Hendrickx, W. Lawrie, M. Russ +6 more·Sep 9, 2020

The prospect of building quantum circuits1,2 using advanced semiconductor manufacturing makes quantum dots an attractive platform for quantum information processing3,4. Extensive studies of various materials have led to demonstrations of two-qubit lo...

MedicinePhysics

Enhancing the Quantum Linear Systems Algorithm Using Richardson Extrapolation

Almudena Carrera Vazquez, R. Hiptmair, Stefan Woerner·Sep 9, 2020

We present a quantum algorithm to solve systems of linear equations of the form Ax=b, where A is a tridiagonal Toeplitz matrix and b results from discretizing an analytic function, with a circuit complexity of O(1/√ε, poly (log κ, log N)), where N de...

Computer SciencePhysicsMathematics

Design of a quantum repeater using quantum circuits and benchmarking its performance on an IBM quantum computer

Sowmitra Das, Md. Saifur Rahman, Mahbubon N. Majumdar·Sep 9, 2020

Quantum communication relies on the existence of entanglement between two nodes of a network. However, due to its fragile nature, it is nearly impossible to establish entanglement at large distances through the direct transmission of qubits. Quantum ...

Computer SciencePhysics

Efficient classical computation of expectation values in a class of quantum circuits with an epistemically restricted phase space representation

A. Budiyono, H. Dipojono·Sep 8, 2020

We devise a classical algorithm which efficiently computes the quantum expectation values arising in a class of continuous variable quantum circuits wherein the final quantum observable—after the Heisenberg evolution associated with the circuits—is a...

PhysicsMedicineMathematics

Quantum Computation of Finite-Temperature Static and Dynamical Properties of Spin Systems Using Quantum Imaginary Time Evolution

Shi-Ning Sun, M. Motta, Ruslan N. Tazhigulov +3 more·Sep 8, 2020

Developing scalable quantum algorithms to study finite-temperature physics of quantum many-body systems has attracted considerable interest due to recent advancements in quantum hardware. However, such algorithms in their present form require resourc...

Computer SciencePhysics

Estimating the degree of non-Markovianity using machine learning

F. Fanchini, G. Karpat, D. Z. Rossatto +2 more·Sep 8, 2020

In the last few years, the application of machine learning methods has become increasingly relevant in different fields of physics. One of the most significant subjects in the theory of open quantum systems is the study of the characterization of non...

Physics

Simulation of wave-particle duality in multipath interferometers on a quantum computer

Mirko Amico, Christoph Dittel·Sep 8, 2020

We present an architecture to investigate wave-particle duality in $N$-path interferometers on a universal quantum computer involving as low as $2{log}_{2}N$ qubits and develop a measurement scheme that allows the efficient extraction of quantifiers ...

Physics

Quantum Walks

J. Guan, Qisheng Wang, M. Ying·Sep 8, 2020

We present a novel application of the HHL (Harrow-Hassidim-Lloyd) algorithm --- a quantum algorithm solving systems of linear equations --- in solving an open problem about quantum walks, namely computing hitting (or absorption) probabilities of a ge...

Computer SciencePhysics

Thermal Operations in general are not memoryless

Hanna Wojewódka-Ściążko, Maciej Stankiewicz, Edgar A. Aguilar +6 more·Sep 7, 2020

So-called Thermal Operations seem to describe the most fundamental and reasonable set of operations allowable for state transformations at an ambient inverse temperature $β$. However, a priori, they require experimentalists to manipulate very complex...

Quantum Physics

Fast simulation of planar Clifford circuits

David Gosset, D. Grier, A. Kerzner +1 more·Sep 7, 2020

A general quantum circuit can be simulated classically in exponential time. If it has a planar layout, then a tensor-network contraction algorithm due to Markov and Shi has a runtime exponential in the square root of its size, or more generally expon...

Computer ScienceMathematicsPhysics

Exponential speedup in measuring out-of-time-ordered correlators with a single bit of quantum information

P. Sreeram, Naga Dileep Varikuti, V. Madhok·Sep 7, 2020

Out-of-time-ordered correlators (OTOC) are a quantifier of quantum information scrambling and quantum chaos. We propose an efficient quantum algorithm to measure OTOCs that provides an exponential speed-up over the best known classical algorithm prov...

Physics

Efficient calculation of gradients in classical simulations of variational quantum algorithms

Tyson Jones, Julien Gacon·Sep 6, 2020

Calculating the energy gradient in parameter space has become an almost ubiquitous subroutine of variational near-term quantum algorithms. "Faithful" classical emulation of this subroutine mimics its quantum evaluation, and scales as O(P^2) gate oper...

Computer SciencePhysics

Entanglement swapping theory and beyond

Zhaoxu Ji, Huanguo Zhang·Sep 5, 2020

We focus on the general theory of entanglement swapping, including entanglement swapping of pure and mixed states. We also study the theory of entangled swapping chains, which can be regarded as an application of entangled swapping. For maximally ent...

Quantum Physics
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