6,210 research outputs found
Azimuthal angle for boson-jet production in the back-to-back limit
We show for the first time that the azimuthal angle between a vector boson
and a jet, when using the Winner-Take-All recombination scheme, can be
predicted at high precision in the back-to-back limit in the transverse plane.
Specifically, we present a factorization theorem, and obtain numerical
predictions at next-to-next-to-leading logarithmic (NNLL) accuracy. To allow
for improved angular resolution, we provide results for track-based jet
reconstruction, which only requires minimal changes in the calculation. We also
find that linearly-polarized transverse momentum dependent (TMD) beam and jet
functions enter at next-to-leading order (NLO) in the factorization theorem,
originating from spin superpositions for one gluon, rather than the known case
of spin correlations between gluons. We validate the switch from calorimetry to
tracks using Pythia, and confirm the presence of linearly-polarized TMD
functions using MCFM.Comment: 6 pages, 4 figure
Higher-order solutions to non-Markovian quantum dynamics via hierarchical functional derivative
Solving realistic quantum systems coupled to an environment is a challenging
task. Here we develop a hierarchical functional derivative (HFD) approach for
efficiently solving the non-Markovian quantum trajectories of an open quantum
system embedded in a bosonic bath. An explicit expression for arbitrary order
HFD equation is derived systematically. Moreover, it is found that for an
analytically solvable model, this hierarchical equation naturally terminates at
a given order and thus becomes exactly solvable. This HFD approach provides a
systematic method to study the non-Markovian quantum dynamics of an open system
coupled to a bosonic environment.Comment: 5 pages, 2 figure
Separation of endo-polygalacturonase using aqueous two-phase partitioning
The partitioning of endo-polygalacturonase (endo-PG) in polyethylene glycol (PEG)–polyvinyl alcohol (PVA10 000) and
PEG–hydroxypropyl starch (Reppal PES100) aqueous two-phase systems was studied, and revealed the possibility of using
aqueous two-phase extraction to purify and concentrate endo-PG from its clarified fermentation broth. For the PEG8000–
PVA10 000 system, endo-PG presented in the fermentation broth (at concentration that is more than 40% of total protein)
mainly dominates in the top phase with a partitioning coefficient of 6, while total protein concentrates in the bottom phase. A
separation scheme consisting of two consecutive aqueous two-phase extraction steps was proposed: a first extraction in
polyethylene glycol (PEG8000)–polyvinyl alcohol system, followed by a second extraction in PEG8000–(NH4)2SO4 system. This allowed the separation of endo-PG from polymer and the recycling of PEG polymer, since endo-PG was very
strongly partitioned into the bottom phase of the PEG8000–(NH4)2SO4 system. Laboratory-scale experiments were performed to test the efficiency of this scheme. It was found that enzyme recovery was up to 91% with a total purification
factor of about 1.9 and a concentration factor of more than 5. About 90% of the total PEG added into the systems can be
recovered, and no reduction was obtained in the purification factor using recycled PEG.Fundação para a Ciência e a Tecnologia (FCT) – PRAXIS XXI.CEC (INCO-DC) - contract number ERB IC18 CT97 0182
Aqueous two-phase extraction using thermoseparating polymer : a new system for the separation of endo-polygalacturonase
Aqueous two-phase partitioning of endo-polygalacturonase (endo-PG) produced by Kluyveromyces marxianus strains was studied,
on systems containing the thermoseparating polymer Ucon 50-HB-5100 (a random copolymer of 50% ethylene oxide (EO) and 50%
propylene oxide (PO)) as one of the phase-forming compounds. Ucon 50-HB-5100 (Ucon)–polyvinyl alcohol (PVA 10,000), Ucon
50-HB-5100–hydroxypropyl starch (Reppal PES100) and Ucon 50-HB-5100–(NH4)2SO4 systems were tested. Ucon recycling was also
investigated. Ucon–(NH4)2SO4 system proved to be the most efficient system for aqueous two-phase extraction (ATPE) of endo-PG as
when compared to total protein partition, the enzyme was strongly partitioned to the salt-rich phase.
Using Ucon–(NH4)2SO4 system, a separation scheme consisting of three stages was proposed and tested at laboratory scale. In the first
and second stages, operated in series, extractions were performed using the same Ucon–(NH4)2SO4 system. Ucon recycling was done in
each stage. In the third stage, removal of the Ucon and salt residues present in the enzyme-rich phase of the second extraction stage was
done. The proposed scheme allowed for a 10-fold enzyme concentration and a purification factor close to the expected maximum while
maintaining more than 95% of the initial enzyme activity.Fundação para a Ciência e a Tecnologia (FCT) – PRAXIS XXI.INCO DC - ERB IC18 CT97 0182
Dynamical invariants in non-Markovian quantum state diffusion equation
We find dynamical invariants for open quantum systems described by the
non-Markovian quantum state diffusion (QSD) equation. In stark contrast to
closed systems where the dynamical invariant can be identical to the system
density operator, these dynamical invariants no longer share the equation of
motion for the density operator. Moreover, the invariants obtained with from
bi-orthonormal basis can be used to render an exact solution to the QSD
equation and the corresponding non-Markovian dynamics without using master
equations or numerical simulations. Significantly we show that we can apply
these dynamic invariants to reverse-engineering a Hamiltonian that is capable
of driving the system to the target state, providing a novel way to design
control strategy for open quantum systems.Comment: 6 pages, 2 figure
- …