相关论文: Evidence for evolution from pure states to mixed s…
Unitary evolution from pure initial states to pure final states in pi(-)p-> pi(-)pi(+)n imposes constraints on pion production amplitudes that are violated by CERN data on polarized target at 17.2 GeV/c. The pion creation is a non-unitary…
Unitary evolution law describes isolated particle scattering processes in an empty Minkowski spacetime. We put forward a hypothesis that the physical Universe includes a quantum environment that interacts with particle scattering processes.…
Incoherent pion electroproduction on the deuteron is studied from threshold up to the second resonance region with special emphasis on the influence of final state interaction, in particular on polarization observables. The elementary…
A recent proposal of Sjoqvist et.al. to extend Pancharatnam's criterion for phase difference between two different pure states to the case of mixed states in quantum mechanics is analyzed and the existence of phase singularities in the…
Repeated observations of a quantum system interacting with another one can drive the latter toward a particular quantum state, irrespectively of its initial condition, because of an {\em effective non-unitary evolution}. If the target state…
System-environment interaction may introduce dynamic destruction of quantum coherence, resulting in a special representation named as pointer states. Here, pointer states of an open electronic system are studied. The decoherence effect is…
Many-body open quantum systems balance internal dynamics against decoherence from interactions with an environment. Here, we explore this balance via random quantum circuits implemented on a trapped ion quantum computer, where the system…
We show that in photoproduction experiments there are propitious conditions to study the exotic state $1^{-+}$ in the $\pi\eta$ and $\pi\eta'$ channels. We show that for unpolarized photon beam the contributions with natural and unnatural…
In a neutron polarimetry experiment the mixed state relative phases between spin eigenstates are determined from the maxima and minima of measured intensity oscillations. We consider evolutions leading to purely geometric, purely dynamical…
Evolution of purity in case of factorizable interaction between an open system and an environment is investigated. We derive a simple expression for purity decrease at the first instants of evolution (when purity is close to unity). We find…
We address the problem of pion production in low energy $\pi$-nucleus collisions. For the production mechanism we assume a simple model consisting of a coherent sum of single pion exchange and the excitation---followed by the decay into two…
In order to resolve the measurement problem of Quantum Mechanics, non-unitary time evolution has been derived from the unitarity of standard quantum formalism. New wave functions of free and non-free quantum systems follow from Schroedinger…
We present the first amplitude analysis of the CERN data on pi(-)p->pi(-)pi(+)n on polarized target at 17.2 GeV/c for dipion masses 580-1080 MeV at low momentum transfer using spin mixing mechanism. The analysis of the S- and P-wave…
In the formulation of Banks, Peskin and Susskind, we show that one can construct evolution equations for the quantum mechanical density matrix $\rho$ with operators which do not commute with hamiltonian which evolve pure states into mixed…
In Part I. of this work we have presented evidence that the measured relative phases of transversity amplitudes in piN->pipiN processes differ from those predicted by the unitary evolution law. We ascribed this difference to a non-unitary…
We propose a theory which exploits the charge-exchange reactions ($^3$He,$^3$H$\pi^+$) and (p,n$\pi^+$) as effective sources of virtual pions. We consider processes in which the creation of virtual pions is followed by conventional…
We investigate the evolution of open quantum systems in the presence of initial correlations with an environment. Here the standard formalism of describing evolution by completely positive trace preserving (CPTP) quantum operations can fail…
The radical departure from classical physics implies quantum coherence, i.e., coherent superposition of eigenstates of Hermitian operators with a discrete spectrum. In resource theory, quantum coherence is a resource for quantum operations.…
Incoherent pion photoproduction on the deuteron is studied for photon energies from threshold up to 1 GeV with special emphasis on polarization observables. The elementary $\gamma N\to\pi N$ amplitude is taken from the MAID model. The…
The measurements of reactions $\pi^- p \to \pi^- \pi^+ n$ and $\pi^+ n \to \pi^+ \pi^- p$ on polarized targets at CERN found a strong dependence of pion production amplitudes on nucleon spin. Analyses of recent measurements of $\pi^- p \to…