Quantum Brain

Papers

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

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13,351 papers in 12 months (+7% vs prior quarter)

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Qubit Platforms

Hardware platform mentions in abstractsPhotonic leads

4,120 papers found

Propagation of generalized Pauli errors in qudit Clifford circuits

Daniel Miller, T. Holz, H. Kampermann +1 more·Jul 16, 2018

It is important for performance studies in quantum technologies to analyze quantum circuits in the presence of noise. We introduce an error probability tensor, a tool to track generalized Pauli error statistics of qudits within quantum circuits compo...

PhysicsMathematics

Constructing Smaller Pauli Twirling Sets for Arbitrary Error Channels

Z. Cai, S. Benjamin·Jul 13, 2018

Twirling is a technique widely used for converting arbitrary noise channels into Pauli channels in error threshold estimations of quantum error correction codes. It is vitally useful both in real experiments and in classical quantum simulations. Mini...

PhysicsMedicine

Hamiltonian simulation with nearly optimal dependence on spectral norm

G. Low·Jul 11, 2018

We present a quantum algorithm for approximating the real time evolution e−iHt of an arbitrary d-sparse Hamiltonian to error є, given black-box access to the positions and b-bit values of its non-zero matrix entries. The query complexity of our algor...

PhysicsComputer ScienceMathematics

Dephasing-Insensitive Quantum Information Storage and Processing with Superconducting Qubits.

Q. Guo, Shi-Biao Zheng, Jianwen Wang +11 more·Jul 10, 2018

A central task towards building a practical quantum computer is to protect individual qubits from decoherence while retaining the ability to perform high-fidelity entangling gates involving arbitrary two qubits. Here we propose and demonstrate a deph...

MedicinePhysics

Black-Box Quantum State Preparation without Arithmetic.

Y. Sanders, G. Low, A. Scherer +1 more·Jul 9, 2018

Black-box quantum state preparation is an important subroutine in many quantum algorithms. The standard approach requires the quantum computer to do arithmetic, which is a key contributor to the complexity. Here we present a new algorithm that avoids...

MedicinePhysics

An efficient quantum circuits optimizing scheme compared with QISKit

Xin Zhang, Hong Xiang, Tao Xiang +2 more·Jul 4, 2018

Recently, the development of quantum chips has made great progress-- the number of qubits is increasing and the fidelity is getting higher. However, qubits of these chips are not always fully connected, which sets additional barriers for implementing...

Computer SciencePhysics

Encoding a qubit in a trapped-ion mechanical oscillator

C. Fluhmann, T. Nguyen, M. Marinelli +3 more·Jul 3, 2018

The stable operation of quantum computers will rely on error correction, in which single quantum bits of information are stored redundantly in the Hilbert space of a larger system. Such encoded qubits are commonly based on arrays of many physical qub...

PhysicsMedicine

Quantum-assisted quantum compiling

Sumeet Khatri, Ryan Larose, Alexander Poremba +3 more·Jul 2, 2018

Compiling quantum algorithms for near-term quantum computers (accounting for connectivity and native gate alphabets) is a major challenge that has received significant attention both by industry and academia. Avoiding the exponential overhead of clas...

Computer SciencePhysics

Molecular realization of a quantum NAND tree

Phillip W K Jensen, Chengjun Jin, Pierre-Luc Dallaire-Demers +2 more·Jun 27, 2018

The negative-AND (NAND) gate is universal for classical computation making it an important target for development. A seminal quantum computing algorithm by Farhi, Goldstone and Gutmann has demonstrated its realization by means of quantum scattering y...

Physics

Entanglement spectroscopy with a depth-two quantum circuit

Yiğit Subaşı, L. Cincio, Patrick J. Coles·Jun 22, 2018

Noisy intermediate-scale quantum (NISQ) computers have gate errors and decoherence, limiting the depth of circuits that can be implemented on them. A strategy for NISQ algorithms is to reduce the circuit depth at the expense of increasing the qubit c...

Physics

A Universal Quantum Computing Virtual Machine

Qiantan Hong, Zi-Yong Ge, Wen Wang +8 more·Jun 18, 2018

A medium-scale quantum computer with full universal quantum computing capability is necessary for various practical aims and testing applications. Here we report a 34-qubit quantum virtual machine (QtVM) based on a medium server. Our QtVM can run qua...

PhysicsMathematics

Variational quantum algorithms for discovering Hamiltonian spectra

Suguru Endo, Tyson Jones, Sam McArdle +2 more·Jun 14, 2018

Calculating the energy spectrum of a quantum system is an important task, for example to analyse reaction rates in drug discovery and catalysis. There has been significant progress in developing algorithms to calculate the ground state energy of mole...

Physics

Quantum simulation of the Sachdev-Ye-Kitaev model by asymmetric qubitization

R. Babbush, D. Berry, H. Neven·Jun 7, 2018

We show that one can quantum simulate the dynamics of a Sachdev-Ye-Kitaev model with $N$ Majorana modes for time $t$ to precision $\epsilon$ with gate complexity $O(N^{7/2} t + N^{5/2} t \,{\rm polylog}(N/ \epsilon))$. In addition to scaling sublinea...

PhysicsMathematics

Experimental Realization of Controlled Square Root of Z Gate Using IBM's Cloud Quantum Experience Platform

Petar Nikolov, V. Galabov·Jun 7, 2018

Quantum computers form a technological cluster with huge growth in the last few years. Although this technology is of still very limited size: perhaps the reason it is not seen as a technology which may be mass produced or of public use in the near f...

PhysicsMathematics

Fault-Tolerant Logical Gates in the IBM Quantum Experience.

R. Harper, S. Flammia·Jun 6, 2018

Quantum computers will require encoding of quantum information to protect them from noise. Fault-tolerant quantum computing architectures illustrate how this might be done but have not yet shown a conclusive practical advantage. Here we demonstrate t...

Computer SciencePhysicsMedicine

Fast universal logical gates on topologically encoded qubits at arbitrarily large code distances

Guanyu Zhu, A. Lavasani, M. Barkeshli·Jun 6, 2018

A fundamental question in the theory of quantum computation is to understand the ultimate space-time resource costs for performing a universal set of logical quantum gates to arbitrary precision. To date, all proposed schemes for implementing a unive...

Physics

On the depth overhead incurred when running quantum algorithms on near-term quantum computers with limited qubit connectivity

Steven Herbert·May 31, 2018

This paper addresses the problem of finding the depth overhead that will be incurred when running quantum circuits on near-term quantum computers. Specifically, it is envisaged that near-term quantum computers will have low qubit connectivity: each q...

MathematicsComputer SciencePhysics

Gradient-based closed-loop quantum optimal control in a solid-state two-qubit system

Guanru Feng, F. Cho, Hemant Katiyar +4 more·May 29, 2018

Quantum optimal control can play a crucial role to realize a set of universal quantum logic gates with error rates below the threshold required for fault-tolerance. Open-loop quantum optimal control relies on accurate modeling of the quantum system u...

Physics

8×8 reconfigurable quantum photonic processor based on silicon nitride waveguides.

C. Taballione, T. Wolterink, J. Lugani +10 more·May 28, 2018

The development of large-scale optical quantum information processing circuits ground on the stability and reconfigurability enabled by integrated photonics. We demonstrate a reconfigurable 8×8 integrated linear optical network based on silicon nitri...

PhysicsMedicine

Hybrid Programming for Near-Term Quantum Computing Systems

A. McCaskey, E. Dumitrescu, D. Liakh +1 more·May 23, 2018

Recent computations involving quantum processing units (QPUs)have demonstrated a series of challenges inherent to hybrid classical-quantum programming, compilation, execution, and verification and validation. Despite considerable progress, system-lev...

Computer ScienceMathematicsPhysics
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