542 research outputs found
Open Quantum System Dynamics from Infinite Tensor Network Contraction
Recently developed methods to compute dynamics of strongly coupled
non-Markovian open systems are based on a representation of the so-called
process tensor in terms of a tensor network, which can be contracted to matrix
product state (MPS) form. We show that for Gaussian environments the
stationarity of the bath response can be exploited in order to construct this
MPS using infinite MPS evolution methods. The result structurally resembles
open system evolution with auxiliary degrees of freedom, as in hierarchical or
pseudomode methods. Here, however, these degrees of freedom are generated
automatically by the MPS evolution algorithm. Furthermore, our algorithm for
contracting the process tensor network leads to significant computational
speed-ups for strong coupling problems over existing proposals
Non-Markovian Quantum Dynamics in a Squeezed Reservoir
We study non-Markovian dynamics of an open quantum system system interacting with a nonstationary squeezed bosonic reservoir. We derive exact and approximate descriptions for the open system dynamics. Focusing on the spin boson model, we compare exact dynamics with Redfield theory and a quantum optical master equation for both short and long time dynamics and in non-Markovian and Markov regimes. The squeezing of the bath results in asymptotic oscillations in the stationary state, which are captured faithfully by the Redfield master equation in the case of weak coupling. Furthermore, we find that the bath squeezing direction modifies the effective system-environment coupling strength and, thus, the strength of the dissipation
Therapeutic protein transduction of mammalian cells and mice by nucleic acid-free lentiviral nanoparticles
The straightforward production and dose-controlled administration of protein therapeutics remain major challenges for the biopharmaceutical manufacturing and gene therapy communities. Transgenes linked to HIV-1-derived vpr and pol-based protease cleavage (PC) sequences were co-produced as chimeric fusion proteins in a lentivirus production setting, encapsidated and processed to fusion peptide-free native protein in pseudotyped lentivirions for intracellular delivery and therapeutic action in target cells. Devoid of viral genome sequences, protein-transducing nanoparticles (PTNs) enabled transient and dose-dependent delivery of therapeutic proteins at functional quantities into a variety of mammalian cells in the absence of host chromosome modifications. PTNs delivering Manihot esculenta linamarase into rodent or human, tumor cell lines and spheroids mediated hydrolysis of the innocuous natural prodrug linamarin to cyanide and resulted in efficient cell killing. Following linamarin injection into nude mice, linamarase-transducing nanoparticles impacted solid tumor development through the bystander effect of cyanid
Therapeutic protein transduction of mammalian cells and mice by nucleic acid-free lentiviral nanoparticles
The straightforward production and dose-controlled administration of protein therapeutics remain major challenges for the biopharmaceutical manufacturing and gene therapy communities. Transgenes linked to HIV-1-derived vpr and pol-based protease cleavage (PC) sequences were co-produced as chimeric fusion proteins in a lentivirus production setting, encapsidated and processed to fusion peptide-free native protein in pseudotyped lentivirions for intracellular delivery and therapeutic action in target cells. Devoid of viral genome sequences, protein-transducing nanoparticles (PTNs) enabled transient and dose-dependent delivery of therapeutic proteins at functional quantities into a variety of mammalian cells in the absence of host chromosome modifications. PTNs delivering Manihot esculenta linamarase into rodent or human, tumor cell lines and spheroids mediated hydrolysis of the innocuous natural prodrug linamarin to cyanide and resulted in efficient cell killing. Following linamarin injection into nude mice, linamarase-transducing nanoparticles impacted solid tumor development through the bystander effect of cyanide
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