title: Observation of Time-Invariant Coherence in a Nuclear Magnetic Resonance Quantum Simulator.
abstract: The ability to live in coherent superpositions is a signature trait of quantum systems and constitutes an irreplaceable resource for quantum-enhanced technologies. However, decoherence effects usually destroy quantum superpositions. It was recently predicted that, in a composite quantum system exposed to dephasing noise, quantum coherence in a transversal reference basis can stay protected for an indefinite time. This can occur for a class of quantum states independently of the measure used to quantify coherence, and it requires no control on the system during the dynamics. Here, such an invariant coherence phenomenon is observed experimentally in two different setups based on nuclear magnetic resonance at room temperature, realizing an effective quantum simulator of two- and four-qubit spin systems. Our study further reveals a novel interplay between coherence and various forms of correlations, and it highlights the natural resilience of quantum effects in complex systems.
authors: Instituto de Física de São Carlos, Universidade de São Paulo, CP 369, 13560-970 São Carlos, São Paulo, Brazil.|School of Mathematical Sciences, The University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom.
authors: Isabela A
authors: IA
authors: Silva
authors: Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro, Rio de Janeiro, Brazil.
authors: Alexandre M
authors: AM
authors: Souza
authors: School of Mathematical Sciences, The University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom.
authors: Thomas R
authors: TR
authors: Bromley
authors: School of Mathematical Sciences, The University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom.|Dipartimento di Fisica "E. R. Caianiello,"Università degli Studi di Salerno, Via Giovanni Paolo II, I-84084 Fisciano (SA), Italy.
authors: Marco
authors: M
authors: Cianciaruso
authors: Department of Chemistry, Technische Universität München, Lichtenbergstraße 4, 85747 Garching, Germany.
authors: Raimund
authors: R
authors: Marx
authors: Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro, Rio de Janeiro, Brazil.
authors: Roberto S
authors: RS
authors: Sarthour
authors: Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro, Rio de Janeiro, Brazil.
authors: Ivan S
authors: IS
authors: Oliveira
authors: Instituto de Física de São Carlos, Universidade de São Paulo, CP 369, 13560-970 São Carlos, São Paulo, Brazil.|School of Mathematical Sciences, The University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom.|Dipartimento di Energia, Ingegneria dell'Informazione e Modelli Matematici, Università di Palermo, Viale delle Scienze, Edificio 9, 90128 Palermo, Italy.|Dipartimento di Fisica e Chimica, Università di Palermo, Via Archirafi 36, 90123 Palermo, Italy.
authors: Rosario
authors: R
authors: Lo Franco
authors: Department of Chemistry, Technische Universität München, Lichtenbergstraße 4, 85747 Garching, Germany.
authors: Steffen J
authors: SJ
authors: Glaser
authors: Instituto de Física de São Carlos, Universidade de São Paulo, CP 369, 13560-970 São Carlos, São Paulo, Brazil.
authors: Eduardo R
authors: ER
authors: deAzevedo
authors: Instituto de Física de São Carlos, Universidade de São Paulo, CP 369, 13560-970 São Carlos, São Paulo, Brazil.
authors: Diogo O
authors: DO
authors: Soares-Pinto
authors: School of Mathematical Sciences, The University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom.
authors: Gerardo
authors: G
authors: Adesso