Forming Superposition States

Chon‐Fai Kam, Wei-Min Zhang, D.H. Feng

D. W. Hallwood, Jacob Dunningham, Keith R. Burnett

Quantum behaviour appears to be lost in macroscopic objects. They do not, for example, form superpositions. In this paper I present two schemes that produce multiparticle superpositions of superfluid flow. By studying the effect of external parameters on the superposition, I have found three conditions that must be satisfied for a superposition to form. The energy of the superposition states must be close, there must be a coupling path between the states and other states must not couple strongly. By optimising these conditions, it may be possible to make Schrödinger cat states, useful for metrology and stable qubits.

Xiao-Qi Sun, Z. Yang

A general form of dynamical equations is obtained on the requirement of the superposition principle of quantum states; hence the constraints on the forms of the Lagrangians are acquired, under the assumption of correspondence between quantum states and field operators. It shows that the superposition principle requires the continuous transformation group of the Lagrangians to be compact, and that the Lagrangians of elementary particles, such as leptons, quarks, photons and gluons, satisfy this requirement, but the existence of Higgs will break the superposition principle. Typeset using REVTEX 1 I.

Bob Coecke

Jing Liao, Xiaoguang Wang, Ling-An Wu +1 more

The states formed by a superposition of the negative binomial states are introduced. The sub-Poissonian statistics and squeezing properties of the superposition states are studied in detail. Moreover, we obtain the ladder operator formalism of the superposition state and find that this state is a type of two-photon nonlinear coherent state. A scheme for the generation of the superposition state is also discussed.