Papers

Tomoki Tanaka, Shumpei Uno, Tamiya Onodera +2 more·Oct 8, 2021

Many quantum algorithms contain an important subroutine, the quantum amplitude estimation. As the name implies, this is essentially the parameter estimation problem and thus can be handled via the established statistical estimation theory. However, t...

Yu Shee, Pei-Kai Tsai, Chengyun Hong +2 more·Oct 8, 2021

Simulating electronic structure on a quantum computer requires encoding of fermionic systems onto qubits. Common encoding methods transform a fermionic system of $N$ spin-orbitals into an $N$-qubit system, but many of the fermionic configurations do ...

Jakub Marecek, A. Akhriev·Oct 7, 2021

There is an increasing interest in quantum algorithms for optimization problems. Within convex optimization, interior-point methods and other recently proposed quantum algorithms are non-trivial to implement on noisy quantum devices. Here, we discuss...

Yuta Tsuchimoto, Zhe Sun, E. Togan +6 more·Oct 7, 2021

Quantum transduction between the microwave and optical domains is an outstanding challenge for long-distance quantum networks based on superconducting qubits. For all transducers realized to date, the generally weak light-matter coupling does not all...

A. Muñoz-Moller, L. Pereira, L. Zambrano +2 more·Oct 7, 2021

Current noise levels in physical realizations of qubits and quantum operations limit the applicability of conventional methods to characterize entanglement. In this adverse scenario, we follow a quantum variational approach to estimate the geometric ...

D. Halder, V. SrinivasaPrasannaa, Valay Agarawal +1 more·Oct 6, 2021

The iterative quantum phase estimation algorithm, applied to calculating the ground state energies of quantum chemical systems, is theoretically appealing in its wide scope of being able to handle both weakly and strongly correlated regimes. However,...

J. Teske, H. Bluhm·Oct 1, 2021

Realistic modelling of qubit systems including noise and constraints imposed by control hardware is required for performance prediction and control optimization of quantum processors. We introduce qopt, a software framework for simulating qubit dynam...

R. Mezher, James Mills, E. Kashefi·Sep 29, 2021

Correcting errors due to noise in quantum circuits run on current and near-term quantum hardware is essential for any convincing demonstration of quantum advantage. Indeed, in many cases it has been shown that noise renders quantum circuits efficient...

Maxime Tremblay, Nicolas Delfosse, M. Beverland·Sep 29, 2021

Quantum low density parity check (LDPC) codes may provide a path to build low-overhead fault-tolerant quantum computers. However, as general LDPC codes lack geometric constraints, naïve layouts couple many distant qubits with crossing connections whi...

Nicolas Delfosse, M. Beverland, Maxime Tremblay·Sep 29, 2021

In this work we establish lower bounds on the size of Clifford circuits that measure a family of commuting Pauli operators. Our bounds depend on the interplay between a pair of graphs: the Tanner graph of the set of measured Pauli operators, and the ...

A. Sultanov, M. Kuzmanović, A. V. Lebedev +1 more·Sep 28, 2021

We present a method for in situ temperature measurement of superconducting quantum circuits, by using the first three levels of a transmon device to which we apply a sequence of π gates. Our approach employs projective dispersive readout and utilizes...

James R. Wootton·Sep 27, 2021

Matching codes are stabilizer codes based on Kitaev’s honeycomb lattice model. The hexagonal form of these codes are particularly well-suited to the heavy-hexagon device layouts currently pursued in the hardware of IBM quantum. Here we show how the s...

Gaurav Gyawali, M. Lawler·Sep 24, 2021

Approximating the ground states of strongly interacting electron systems in quantum chemistry and condensed matter physics is expected to be one of the earliest applications of quantum computers. In this paper, we prepare highly accurate ground state...

T. Tai, Jingnan Cai, S. Anlage·Sep 24, 2021

Superconducting resonators are widely used in many applications such as qubit readout for quantum computing, and kinetic inductance detectors. These resonators are susceptible to numerous loss and noise mechanisms, especially the dissipation due to t...

Vicente Leyton-Ortega, Tyler Kharazi, R. Pooser·Sep 22, 2021

Quantum Process Tomography (QPT) is a powerful tool to characterize quantum operations, but it requires considerable resources making it impractical for more than 2-qubit systems. This work proposes an alternative approach that requires significantly...

Diego Tielas, M. Losada, L. Rebón +1 more·Sep 22, 2021

When an informationally complete measurement is not available, the reconstruction of the density operator that describes the state of a quantum system can be obtained, in a reliable way, by adopting the maximum entropy principle (MaxEnt principle), a...

M. Dupont, J. Moore·Sep 22, 2021

Quantum criticality emerges from the collective behavior of many interacting quantum particles, often at the transition between different phases of matter. It is one of the cornerstones of condensed matter physics, which we access on noisy intermediat...

Tudor Giurgică-Tiron, S. Johri, Iordanis Kerenidis +6 more·Sep 20, 2021

Amplitude estimation is a fundamental quantum algorithmic primitive that enables quantum computers to achieve quadratic speedups for a large class of statistical estimation problems, including Monte Carlo methods. The main drawback from the perspecti...

Troy J. Sewell, S. Jordan·Sep 20, 2021

Noisy intermediate-scale quantum (NISQ) hardware [1] is typically limited to lowdepth quantum circuits to limit the number of opportunities for introduction of error by unreliable quantum gates. A less-explored alternative approach is to repeatedly a...

Kentaro Yamamoto, D. Manrique, I. Khan +2 more·Sep 17, 2021

Running quantum algorithms on real hardware is essential for understanding their strengths and limitations, especially in the noisy intermediate scale quantum (NISQ) era. Herein we focus on the practical aspect of quantum computational calculations o...