Authors: Espinos, H.; Panadero, I; Garcia-Ripoll, J. J.; Torrontegui, E. Journal: QUANTUM SCIENCE AND TECHNOLOGY Publication date: 2023/04/01 DOI: 10.1088/2058-9565/acbed7 Abstract: We analyze the implementation of a fast nonadiabatic CZ gate between two transmon qubits with tunable coupling. The gate control method is based on a theory of dynamical invariants which leads to reduced leakage [...]
Authors: Cortes-Vega, J.; Barra, J. F.; Pereira, L.; Delgado, A. Journal: QUANTUM INFORMATION PROCESSING Publication date: 2023/05/09 DOI: 10.1007/s11128-023-03953-y Abstract: Entangled states play a fundamental role in quantum mechanics and are at the core of many contemporary applications, such as quantum communication and quantum computing. Therefore, determining whether a state is entangled or not is [...]
Authors: Diez-Valle, Pablo; Luis-Hita, Jorge; Hernandez-Santana, Senaida; Martinez-Garcia, Fernando; Diaz-Fernandez, Alvaro; Andres, Eva; Garcia-Ripoll, Juan Jose; Sanchez-Martinez, Escolastico; Porras, Diego Journal: QUANTUM SCIENCE AND TECHNOLOGY Publication date: 2023/10/01 DOI: 10.1088/2058-9565/ace474 Abstract: Combinatorial optimization problems are ubiquitous in industry. In addition to finding a solution with minimum cost, problems of high relevance involve a number of [...]
Authors: Pereira, L.; Garcia-Ripoll, J. J.; Ramos, T. Journal: NPJ QUANTUM INFORMATION Publication date: 2023/03/04 DOI: 10.1038/s41534-023-00688-7 Abstract: An efficient characterization of QND measurements is an important ingredient toward certifying and improving the performance and scalability of quantum processors. In this work, we introduce a parallel tomography of QND measurements that addresses single- and two-qubit [...]
Authors: Gomez-Leon, Alvaro; Ramos, Tomas; Gonzalez-Tudela, Alejandro; Porras, Diego Journal: QUANTUM Publication date: 2023/05/23 DOI: Abstract: We study the phenomena of topological amplification in arrays of parametric oscillators. We find two phases of topological amplification, both with directional transport and exponential gain with the number of sites, and one of them featuring squeezing. We also [...]
Authors: Bello, M.; Platero, G.; Gonzalez-Tudela, A. Journal: PRX QUANTUM Publication date: 2022/03/07 DOI: 10.1103/PRXQuantum.3.010336 Abstract: Waveguide QED has emerged as a powerful analog quantum simulator due to the possibility of mediating versatile spin-spin interactions with tunable sign, range, and even dimerization. Yet, despite their potential, the many-body phases emerging from these systems have only [...]
Authors: Pereira, Luciano; Zambrano, Leonardo; Delgado, Aldo Journal: NPJ QUANTUM INFORMATION Publication date: 2022/05/13 DOI: 10.1038/s41534-022-00565-9 Abstract: We introduce an inductive n-qubit pure-state estimation method based on projective measurements on mn + 1 separable bases or m entangled bases plus the computational basis, with m >= 2. The method exhibits a favorable scaling in the [...]
Authors: Garbe, Louis; Abah, Obinna; Felicetti, Simone; Puebla, Ricardo Journal: QUANTUM SCIENCE AND TECHNOLOGY Publication date: 2022/06/15 DOI: 10.1088/2058-9565/ac6ca5 Abstract: Phase transitions represent a compelling tool for classical and quantum sensing applications. It has been demonstrated that quantum sensors can in principle saturate the Heisenberg scaling, the ultimate precision bound allowed by quantum mechanics, in [...]
Authors: Munuera-Javaloy, C.; Puebla, R.; D'Anjou, B.; Plenio, M. B.; Casanova, J. Journal: NPJ QUANTUM INFORMATION Publication date: 2022/11/30 DOI: 10.1038/s41534-022-00653-w Abstract: We present a protocol that detects molecular conformational changes with two nitroxide electron-spin labels and a nitrogen-vacancy (NV) center in diamond. More specifically, we demonstrate that the NV can detect energy shifts induced [...]
Authors: Sharafiev, Aleksei; Juan, Mathieu L.; Gargiulo, Oscar; Zanner, Maximilian; Woegerer, Stephanie; Garcia-Ripoll, Juan Jose; Kirchmair, Gerhard Journal: QUANTUM Publication date: 2021/06/10 DOI: 10.22331/q-2021-06-10-474 Abstract: At the dawn of Quantum Physics, Wigner and Weisskopf obtained a full analytical description (a photon portrait) of the emission of a single photon by a twolevel system, using the [...]