Quantum Brain

Papers

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

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31,714

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152

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15,749 papers in 12 months (-37% vs prior quarter)

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31,714 papers found

Quantum Algorithms for the Most Frequently String Search, Intersection of Two String Sequences and Sorting of Strings Problems

K. Khadiev, Artem Ilikaev·Dec 9, 2019

We study algorithms for solving three problems on strings. The first one is the Most Frequently String Search Problem. The problem is the following. Assume that we have a sequence of n strings of length k. The problem is finding the string that occur...

MathematicsComputer SciencePhysics

Coherence in logical quantum channels

Joseph K. Iverson, J. Preskill·Dec 9, 2019

We study the effectiveness of quantum error correction against coherent noise. Coherent errors (for example, unitary noise) can interfere constructively, so that in some cases the average infidelity of a quantum circuit subjected to coherent errors m...

PhysicsComputer Science

Local quantum uncertainty for multipartite quantum systems

Mazhar N. Ali·Dec 9, 2019

Local quantum uncertainty captures purely quantum correlations excluding their classical counterpart. This measure is quantum discord type, however with the advantage that there is no need to carry out the complicated optimization procedure over meas...

Physics

Grover Adaptive Search for Constrained Polynomial Binary Optimization

Austin Gilliam, Stefan Woerner, Constantin Gonciulea·Dec 9, 2019

In this paper we discuss Grover Adaptive Search (GAS) for Constrained Polynomial Binary Optimization (CPBO) problems, and in particular, Quadratic Unconstrained Binary Optimization (QUBO) problems, as a special case. GAS can provide a quadratic speed...

Computer SciencePhysics

Highly Transparent Contacts to the 1D Hole Gas in Ultra-Scaled Ge/Si Core/Shell Nanowires.

M. Sistani, Jovian Delaforce, R. Kramer +10 more·Dec 9, 2019

Semiconductor-superconductor hybrid systems have outstanding potential for emerging high performance nanoelectronics and quantum devices. However, critical to their successful application is the fabrication of high quality and reproducible semiconduc...

PhysicsMedicineMaterials Science

Combating quasiparticle poisoning with multiple Majorana fermions in a periodically-driven quantum wire

R. W. Bomantara, J. Gong·Dec 9, 2019

Quasiparticle poisoning has remained one of the main challenges in the implementation of Majorana-based quantum computing. It inevitably occurs when the system hosting Majorana qubits is not completely isolated from its surrounding, thus considerably...

PhysicsMedicine

Measurement-induced steering of quantum systems

Sthitadhi Roy, J. Chalker, I. Gornyi +2 more·Dec 9, 2019

We set out a general protocol for steering the state of a quantum system from an arbitrary initial state towards a chosen target state by coupling it to auxiliary quantum degrees of freedom. The protocol requires multiple repetitions of an elementary...

Computer SciencePhysics

Implementation of the XY interaction family with calibration of a single pulse

D. Abrams, N. Didier, Blake R. Johnson +2 more·Dec 9, 2019

Near-term applications of quantum information processors will rely on optimized circuit implementations to minimize gate depth and therefore mitigate the impact of gate errors in noisy intermediate-scale quantum (NISQ) computers. More expressive gate...

PhysicsComputer Science

Learning Non-Markovian Quantum Noise from Moiré-Enhanced Swap Spectroscopy with Deep Evolutionary Algorithm

M. Niu, Vadim N. Smelyanskyi, P. Klimov +30 more·Dec 9, 2019

Two-level-system (TLS) defects in amorphous dielectrics are a major source of noise and decoherence in solid-state qubits. Gate-dependent non-Markovian errors caused by TLS-qubit coupling are detrimental to fault-tolerant quantum computation and have...

PhysicsComputer Science

Quantum Attacks without Superposition Queries: the Offline Simon Algorithm

X. Bonnetain, Akinori Hosoyamada, M. Naya-Plasencia +2 more·Dec 8, 2019

In symmetric cryptanalysis, the model of superposition queries has led to surprising results, with many constructions being broken in polynomial time thanks to Simon's period-finding algorithm. But the practical implications of these attacks remain b...

Computer SciencePhysics

Linear multi-particle, multi-port interferometers and their matrix representations

Bülent Demirel·Dec 8, 2019

Interferences in multi-path systems for single and multiple particles are theoretically analyzed. A holistic method is presented, which allows to construct the unitary transition matrix describing interferometers for any port number d and particle nu...

Physics

Initial states for quantum field simulations in phase space

P. Drummond, B. Opanchuk·Dec 8, 2019

Bosonic quantum fields can be simulated with `quantum software' in phase-space. The positive-P, Wigner and Q-function phase-space methods are reviewed. Initial quantum states and boundaries for infinite domains are considered in detail. The quantum i...

Physics

Characterization of exact one-query quantum algorithms

Weijian Chen, Zekun Ye, Lvzhou Li·Dec 7, 2019

The quantum query models is one of the most important models in quantum computing. Several well-known quantum algorithms are captured by this model, including the Deutsch-Jozsa algorithm, the Simon algorithm, the Grover algorithm and others. In this ...

Physics

Unitary-coupled restricted Boltzmann machine ansatz for quantum simulations

Chang-Yu Hsieh, Qiming Sun, Shengyu Zhang +1 more·Dec 6, 2019

Neural-network quantum state (NQS) has attracted significant interests as a powerful wave-function ansatz to model quantum phenomena. In particular, a variant of NQS based on the restricted Boltzmann machine (RBM) has been adapted to model the ground...

Computer SciencePhysics

Continuous Variables Graph States Shaped as Complex Networks: Optimization and Manipulation

F. Sansavini, V. Parigi·Dec 6, 2019

Complex networks structures have been extensively used for describing complex natural and technological systems, like the Internet or social networks. More recently, complex network theory has been applied to quantum systems, where complex network to...

Computer ScienceMedicineMathematicsPhysics

Generation of n -qubit W states using spin torque

Amritesh Sharma, A. Tulapurkar·Dec 6, 2019

We examine here a scheme to generate a W state of an n-qubit system with all-to-all pairwise exchange interaction between n qubits. This relies on sharing of superposed excitations of a smaller number of $q$ qubits among others. We present a bound on...

Physics

Contracting Arbitrary Tensor Networks: General Approximate Algorithm and Applications in Graphical Models and Quantum Circuit Simulations.

Feng Pan, Pengfei Zhou, Sujie Li +1 more·Dec 6, 2019

We present a general method for approximately contracting tensor networks with an arbitrary connectivity. This enables us to release the computational power of tensor networks to wide use in inference and learning problems defined on general graphs. ...

MedicinePhysicsComputer Science

A Quantum Algorithm for Linear PDEs Arising in Finance

F. Fontanela, Antoine Jacquier, Mugad Oumgari·Dec 5, 2019

We propose a hybrid quantum-classical algorithm, originated from quantum chemistry, to price European and Asian options in the Black-Scholes model. Our approach is based on the equivalence between the pricing partial differential equation and the Sch...

MathematicsEconomics

Automated Tuning of Double Quantum Dots into Specific Charge States Using Neural Networks

Renato Durrer, B. Kratochwil, J. Koski +5 more·Dec 5, 2019

While quantum dots are at the forefront of quantum device technology, tuning multi-dot systems requires a lengthy experimental process as multiple parameters need to be accurately controlled. This process becomes increasingly time-consuming and diffi...

Physics

Heuristics for Quantum Compiling with a Continuous Gate Set

M. Davis, Ethan Smith, Ana Tudor +3 more·Dec 5, 2019

We present an algorithm for compiling arbitrary unitaries into a sequence of gates native to a quantum processor. As accurate CNOT gates are hard for the foreseeable Noisy- Intermediate-Scale Quantum devices era, our A* inspired algorithm attempts to...

Computer SciencePhysics
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