4 research outputs found
An overview on Single Apparatus Quantum Measurements
Given the state of a quantum system, one can calculate the expectation value
of any observable of the system. However, the inverse problem of determining
the state by performing different measurements is not a trivial task. In
various experimental setups it is reasonably straightforward to reconstruct the
state of a quantum system employing linear tomographic technique. In this way
the elements of the density matrix can be linearly related to a set of measured
quantities. But since different observables of a quantum system are not
commuting with each other, one often has to perform series of successive
measurements of observables which cannot be done simultaneously. Simultaneous
measurement of observables cost less time and energy and is more beneficial. In
this paper we review the strategy of quantum state tomography with simultaneous
measurement of commuting observables. This can be done by introducing an
assistant system of which the state is known. We show that the interaction
between the assistant and the system of interest within different frame works
allows the reconstruction of the state of the system. Specifically, we consider
a two-level system and reconstruct its initial state by introducing an
assistant which can be either another two-level system or a single cavity mode
of the electromagnetic field.Comment: 11 pages, to be appear in journal of computational and theoretical
nanoscienc
Visualizing the Quantum Interaction Picture in Phase Space
We illustrate the correspondence between the quantum Interaction
Picture-evolution of the state of a quantum system in Hilbert space and a
combination of local and global transformations of its Wigner function in phase
space. To this aim, we consider the time-evolution of a quantized harmonic
oscillator driven by both a linear and a quadratic (in terms of bosonic
creation and annihilation operators) potentials and employ the Magnus series to
derive the exact form of the time-evolution operator. In this case, the
Interaction Picture corresponds to a local transformation of phase
space-reference frame into the one that is co-moving with the Wigner function.Comment: Submitted to New Journal of Physic
Boon, bias or bane? The potential influence of reviewer recommendations on editorial decision-making
No formal investigations have been conducted into the efficacy or potential influence of reviewer recommendations on editorial decisions, and the impact of this on the expectations and behaviour of authors, reviewers and journal editors. This article addresses key questions about this critical aspect of the peer review submission process. We suggest several future steps which could be taken towards improving the review process and make it more transparent, better understood, and fairer for all parties
Gender gap in journal submissions and peer review during the first wave of the COVID-19 pandemic : A study on 2329 Elsevier journals
During the early months of the COVID-19 pandemic, there was an unusually high submission rate of scholarly articles. Given that most academics were forced to work from home, the competing demands for familial duties may have penalized the scientific productivity of women. To test this hypothesis, we looked at submitted manuscripts and peer review activities for all Elsevier journals between February and May 2018-2020, including data on over 5 million authors and referees. Results showed that during the first wave of the pandemic, women submitted proportionally fewer manuscripts than men. This deficit was especially pronounced among more junior cohorts of women academics. The rate of the peer-review invitation acceptance showed a less pronounced gender pattern with women taking on a greater service responsibility for journals, except for health & medicine, the field where the impact of COVID-19 research has been more prominent. Our findings suggest that the first wave of the pandemic has created potentially cumulative advantages for men