192 citations · 1.3k across the 25 of their papers we have counts for
24 papers
Decoherence of electron spin qubit during transfer between two semiconductor quantum dots at low magnetic fields
Jan A. Krzywda, Łukasz Cywiński
Electron shuttling is one of the current avenues being pursued to scale semiconductor quantum dot-based spin qubits. Adiabatic spin qubit transfer along a chain of tunnel-coupled q…
Blueprint of a scalable spin qubit shuttle device for coherent mid-range qubit transfer in disordered Si/SiGe/SiO
Veit Langrock, Jan A. Krzywda, Niels Focke +3
Silicon spin qubits stand out due to their very long coherence times, compatibility with industrial fabrication, and prospect to integrate classical control electronics. To achieve…
Qubit decoherence under two-axis coupling to low-frequency noises
Guy Ramon, Łukasz Cywiński
Many solid-state qubit systems are afflicted by low frequency noise mechanisms that operate along two perpendicular axes of the Bloch sphere. Depending on the qubit's control field…
Statistics of projective measurement on a quantum probe as a witness of noncommutativity of algebra of a probed system
Fattah Sakuldee, Łukasz Cywiński
We consider a quantum probe undergoing pure dephasing due to its interaction with a quantum system . The dynamics of is then described by a well-defined sub-algebra of o…
Mechanisms of optical orientation of an individual Mn ion spin in a II-VI quantum dot
T. Smoleński, Ł. Cywiński, P. Kossacki
We provide a theoretical description of the optical orientation of a single Mn ion spin under quasi-resonant excitation demonstrated experimentally by Goryca et al. [Phys. R…
Accuracy of dynamical-decoupling-based spectroscopy of Gaussian noise
Piotr Szańkowski, Łukasz Cywiński
The fundamental assumption of dynamical decoupling based noise spectroscopy is that the coherence decay rate of qubit (or qubits) driven with a sequence of many pulses, is well app…
Spectrum of the Nuclear Environment for GaAs Spin Qubits
Filip K. Malinowski, Frederico Martins, Łukasz Cywiński +7
Using a singlet-triplet spin qubit as a sensitive spectrometer of the GaAs nuclear spin bath, we demonstrate that the spectrum of Overhauser noise agrees with a classical spin diff…
Conductance oscillations in quantum point contacts of InAs/GaSb heterostructures
Michał Papaj, Łukasz Cywiński, Jerzy Wróbel +1
We study quantum point contacts in two-dimensional topological insulators by means of quantum transport simulations for InAs/GaSb heterostructures and HgTe/(Hg,Cd)Te quantum wells.…
Notch filtering the nuclear environment of a spin qubit
F. K. Malinowski, F. Martins, P. D. Nissen +8
Electron spins in gate-defined quantum dots provide a promising platform for quantum computation. In particular, spin-based quantum computing in gallium arsenide takes advantage of…
Characterization and measurement of qubit-environment entanglement generation during pure dephasing
Katarzyna Roszak, Łukasz Cywiński
We consider the coupling of a qubit in a pure state to an environment in an arbitrary state, and characterize the possibility of qubit-environment entanglement generation during th…
The relation between the quantum discord and quantum teleportation: the physical interpretation of the transition point between different quantum discord decay regimes
Katarzyna Roszak, Łukasz Cywiński
We study quantum teleportation via Bell-diagonal mixed states of two qubits in the context of the intrinsic properties of the quantum discord. We show that when the quantum-correla…
Optical signatures of spin dependent coupling in semimagnetic quantum dot molecules
Ł. Kłopotowski, P. Wojnar, Ł. Cywiński +5
We present photoluminescence studies of CdTe and CdMnTe quantum dots grown in two adjacent layers. We show that when the dots are 8 nm apart, their magnetooptical properties - Zeem…
Dynamics of entanglement of two electron spins interacting with nuclear spin baths in quantum dots
Igor Bragar, Łukasz Cywiński
We study the dynamics of entanglement of two electron spins in two quantum dots, in which each electron is interacting with its nuclear spin environment. Focusing on the case of un…
The dynamics of two entangled qubits exposed to classical noise: role of spatial and temporal noise correlations
P. Szańkowski, M. Trippenbach, Ł. Cywiński +1
We investigate the decay of two-qubit entanglement caused by the influence of classical noise. We consider the whole spectrum of cases ranging from independent to fully correlated…
Dynamical decoupling noise spectroscopy at an optimal working point of a qubit
Łukasz Cywiński
I present a theory of environmental noise spectroscopy via dynamical decoupling of a qubit at an optimal working point. Considering a sequence of pulses and pure dephasing due…
Nonlocal resistance and its fluctuations in microstructures of band-inverted HgTe/(Hg,Cd)Te quantum wells
G. Grabecki, J. Wróbel, M. Czapkiewicz +10
We investigate experimentally transport in gated microsctructures containing a band-inverted HgTe/Hg_{0.3}Cd_{0.7}Te quantum well. Measurements of nonlocal resistances using many c…
Influence of exciton spin relaxation on the photoluminescence spectra of semimagnetic quantum dots
Ł. Kłopotowski, Ł. Cywiński, M. Szymura +8
We present a comprehensive experimental and theoretical studies of photoluminescence of single CdMnTe quantum dots with Mn content x ranging from 0.01 to 0.2. We distinguish three…
Nonperturbative master equation solution of central spin dephasing dynamics
Edwin Barnes, Łukasz Cywiński, S. Das Sarma
We solve the long-standing central spin problem for a general set of inhomogeneous bath couplings and a large class of initial bath states. We compute the time evolution of the coh…
PbTe/PbSnTe heterostructures as analogs of topological insulators
Ryszard Buczko, Łukasz Cywiński
We investigate theoretically the PbTe/PbSnTe heterostructure grown in [111] direction, specifically a quantum wall (potential step of width d) of PbTe embedded in Pb_{1-x}Sn_{x}Te.…
Absence of nonlocal resistance in microstructures of PbTe quantum wells
K. A. Kolwas, G. Grabecki, S. Trushkin +6
We report on experiments allowing to set an upper limit on the magnitude of the spin Hall effect and the conductance by edge channels in quantum wells of PbTe embedded between PbEu…
Scaling of Dynamical Decoupling for Spin Qubits
J. Medford, L. Cywinski, C. Barthel +3
We investigate scaling of coherence time, T2, with the number of π-pulses, n_π, in a singlet- triplet spin qubit using Carr-Purcell-Meiboom-Gill (CPMG) and concatenated dynamical d…
Dephasing of electron spin qubits due to their interaction with nuclei in quantum dots
Łukasz Cywiński
Coherence of spins of electrons confined in III-V quantum dots is strongly affected by their hyperfine interaction with the nuclei. In this paper an introduction to this subject wi…
Optical orientation of a single Mn spin in a quantum dot: Role of carrier spin relaxation
Lukasz Cywinski
In order to explain the recently observed phenomenon of optical orientation of a single Mn spin residing inside a quantum dot, a process of Mn spin relaxation with characteristic t…
Pure quantum dephasing of a solid state electron spin qubit in a large nuclear spin bath coupled by long-range hyperfine-mediated interactions
L. Cywinski, W. M. Witzel, S. Das Sarma
We investigate decoherence due to pure dephasing of a localized spin qubit interacting with a nuclear spin bath. Although in the limit of a very large magnetic field the only decoh…