The determination of the quantum state of a single system by protective observation is used to justify operationally a formulation of quantum theory on the quantum state space (projective Hilbertâ€¦ (More)

An important limitation is shown in the analogy between the Aharonov-Bohm effect and the parallel transport on a cone. It illustrates a basic difference between gravity and gauge fields due to theâ€¦ (More)

We provide a physical prescription based on interferometry for introducing the total phase of a mixed state undergoing unitary evolution, which has been an elusive concept in the past. We define theâ€¦ (More)

Protective measurements, which we have introduced recently, allow to measure properties of the state of a single quantum system and even the SchrÃ¶dinger wave itself. These measurements require aâ€¦ (More)

It is argued that there is no evidence for causality as a metaphysical relation in quantum phenomena. The assumption that there are no causal laws, but only probabilities for physical processesâ€¦ (More)

The non-relativistic formalism introduced by Berry and Robbins that naturally incorporates the spin-statistics connection is generalized rela-tivistically. It is then extended to an arbitraryâ€¦ (More)

When a quantum system evolves so that it returns to its initial physical state, it acquires a 'memory' of this motion in the form of a geometric phase in the wavefunction. This phase has observableâ€¦ (More)

The quantum measurement problem and various unsuccessful attempts to resolve it are reviewed. A suggestion by Diosi and Penrose for the half life of the quantum superposition of two Newtonianâ€¦ (More)

It is argued that quantum mechanics follows naturally from the assumptions that there are no fundamental causal laws but only probabilities for physical processes that are constrained by symmetries,â€¦ (More)