Macroscopic superpositions in Bose-Josephson junctions: Controlling decoherence due to atom losses

Decoherence bypass of macroscopic superpositions in quantum measurement

We study a class of quantum measurement models. A microscopic object is entangled with a macroscopic pointer such that a distinct pointer position is tied to each eigenvalue of the measured object observable. Those different pointer positions mutually decohere under the influence of an environment. Overcoming limitations of previous approaches we (i) cope with initial correlations between point...

Macroscopic superpositions via nested interferometry: finite temperature and decoherence considerations

Recently, there has been much interest in optomechanical devices for the production of macroscopic quantum states. Here we focus on a proposed scheme for achieving macroscopic superpositions via nested interferometry. We consider the effects of finite temperature on the superposition produced. We also investigate in detail the scheme’s feasibility for probing various novel decoherence mechanism...

Macroscopic quantum tunnelling in spin filter ferromagnetic Josephson junctions

The interfacial coupling of two materials with different ordered phases, such as a superconductor (S) and a ferromagnet (F), is driving new fundamental physics and innovative applications. For example, the creation of spin-filter Josephson junctions and the demonstration of triplet supercurrents have suggested the potential of a dissipationless version of spintronics based on unconventional sup...

Mesoscopic quantum superpositions in bimodal Bose-Einstein condensates: decoherence and strategies to counteract it

Resilience to decoherence of the macroscopic quantum superpositions generated by universally covariant optimal quantum cloning

Nicolò Spagnolo,1,2 Fabio Sciarrino,1,3 and Francesco De Martini1,4,* 1Dipartimento di Fisica, Sapienza Università di Roma, piazzale Aldo Moro 5, I-00185 Roma, Italy 2Consorzio Interuniversitario per le Scienze Fisiche della Materia, piazzale Aldo Moro 5, I-00185 Roma, Italy 3Istituto Nazionale di Ottica, largo Fermi 6, I-50125 Firenze, Italy 4Accademia Nazionale dei Lincei, via della Lungara 1...