543 research outputs found
Continuous phase-space representations for finite-dimensional quantum states and their tomography
Continuous phase spaces have become a powerful tool for describing,
analyzing, and tomographically reconstructing quantum states in quantum optics
and beyond. A plethora of these phase-space techniques are known, however a
thorough understanding of their relations was still lacking for
finite-dimensional quantum states. We present a unified approach to continuous
phase-space representations which highlights their relations and tomography.
The infinite-dimensional case from quantum optics is then recovered in the
large-spin limit.Comment: 15 pages, 9 figures, v4: extended tomography analysis, added
references and figure
Time-optimal polarization transfer from an electron spin to a nuclear spin
Polarization transfers from an electron spin to a nuclear spin are essential
for various physical tasks, such as dynamic nuclear polarization in nuclear
magnetic resonance and quantum state transformations on hybrid electron-nuclear
spin systems. We present time-optimal schemes for electron-nuclear polarization
transfers which improve on conventional approaches and will have wide
applications.Comment: 11 pages, 8 figure
Fast computation of spherical phase-space functions of quantum many-body states
Quantum devices are preparing increasingly more complex entangled quantum
states. How can one effectively study these states in light of their increasing
dimensions? Phase spaces such as Wigner functions provide a suitable framework.
We focus on phase spaces for finite-dimensional quantum states of single qudits
or permutationally symmetric states of multiple qubits. We present methods to
efficiently compute the corresponding phase-space functions which are at least
an order of magnitude faster than traditional methods. Quantum many-body states
in much larger dimensions can now be effectively studied by experimentalists
and theorists using these phase-space techniques.Comment: 12 pages, 3 figure
The future of insurance intermediation in the age of the digital platform economy
Today most insurance is sold by over a million brokers and independent agents acting as intermediaries between the insurance companies and their customers. Digitalization and changing customer behavior have fostered the development of insurtech businesses, and, more recently, multi-sided platforms are emerging as new market forms for insurance intermediation. This paper aims to provide a better understanding of how the emergence of the platform economy with a market dominated by multi-sided platforms potentially impacts insurance intermediation in the future. Using inductive content analysis on the results of a systematic literature review of the body of research on insurance intermediation, we identify the key functional roles fulfilled by insurance intermediaries. Applying these roles to a literature review on multi-sided platforms allows us to compare how different market forms and players embody the functional roles of intermediaries. Our findings suggest that multi-sided platforms are better able to perform certain roles in terms of agility, scale and scope, and we discuss the future role of platforms in insurance intermediation
Insect eggs induce a systemic acquired resistance in Arabidopsis.
Although they constitute an inert stage of the insect's life, eggs trigger plant defences that lead to egg mortality or attraction of egg parasitoids. We recently found that salicylic acid (SA) accumulates in response to oviposition by the Large White butterfly Pieris brassicae, both in local and systemic leaves, and that plants activate a response that is similar to the recognition of pathogen-associated molecular patterns (PAMPs), which are involved in PAMP-triggered immunity (PTI). Here we discovered that natural oviposition by P. brassicae or treatment with egg extract inhibit growth of different Pseudomonas syringae strains in Arabidopsis through the activation of a systemic acquired resistance (SAR). This egg-induced SAR involves the metabolic SAR signal pipecolic acid, depends on ALD1 and FMO1, and is accompanied by a stronger induction of defence genes upon secondary infection. Although P. brassicae larvae showed a reduced performance when feeding on Pseudomonas syringae-infected plants, this effect was less pronounced when infected plants had been previously oviposited. Altogether, our results indicate that egg-induced SAR might have evolved as a strategy to prevent the detrimental effect of bacterial pathogens on feeding larvae
A high-precision polarimeter
We have built a polarimeter in order to measure the electron beam
polarization in hall C at JLAB. Using a superconducting solenoid to drive the
pure-iron target foil into saturation, and a symmetrical setup to detect the
Moller electrons in coincidence, we achieve an accuracy of <1%. This sets a new
standard for Moller polarimeters.Comment: 17 pages, 9 figures, submitted to N.I.
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