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The quantum spin Hall state is a topologically non-trivial insulator state protected by the time reversal symmetry. We show that such a state always leads to spin-charge separation in the presence of a $\pi$ flux. Our result is generally…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Xiao-Liang Qi , Shou-Cheng Zhang

We present practical methods to measure entanglement for quantum simulators that can be realized with trapped ions, cold atoms, and superconducting qubits. Focussing on long- and short-range Ising-type Hamiltonians, we introduce schemes…

Quantum Physics · Physics 2016-03-23 O. Marty , M. Cramer , M. B. Plenio

Spin-orbit interaction provides a spin filtering effect in carbon nanotube based Cooper pair splitters that allows us to determine spin correlators directly from current measurements. The spin filtering axes are tunable by a global external…

Mesoscale and Nanoscale Physics · Physics 2013-10-01 Bernd Braunecker , Pablo Burset , Alfredo Levy Yeyati

Spin bath polarization is the key to enhancing the sensitivity of quantum sensing and information processing. Significant effort has been invested in identifying the consequences of quantumness and its control for spin-bath polarization.…

Quantum phenomena such as entanglement provide powerful resources for enhancing classical sensing. Here, we theoretically show that collective entanglement of spin qubits, arising from a condensation of particle-hole pairs, can strongly…

Due to the spin-orbital coupling in a semiconductor quantum dot, a freely precessing electron spin produces a time-dependent charge density. This creates a sizeable electric field outside the dot, leading to promising applications in…

Mesoscale and Nanoscale Physics · Physics 2008-04-12 L. S. Levitov , E. I. Rashba

We analyze local spin-echo procedures to protect entanglement between two non-interacting qubits, each subject to pure-dephasing random telegraph noise. For superconducting qubits this simple model captures characteristic features of the…

Capacitively coupled semiconductor spin qubits hold promise as the building blocks of a scalable quantum computing architecture with long-range coupling between distant qubits. However, the two-qubit gate fidelities achieved in experiments…

Mesoscale and Nanoscale Physics · Physics 2015-10-29 Xin Wang , Edwin Barnes , S. Das Sarma

We evaluate the spin density oscillations arising in quantum spin Hall quantum dots created via two localized magnetic barriers. The combined presence of magnetic barriers and spin-momentum locking, the hallmark of topological insulators,…

Mesoscale and Nanoscale Physics · Physics 2013-06-24 Giacomo Dolcetto , Niccolò Traverso Ziani , Matteo Biggio , Fabio Cavaliere , Maura Sassetti

The realization of a viable semiconductor transistor and information processing devices based on the electron spin has fueled intense basic research of three key elements: injection, detection, and manipulation of spins in the semiconductor…

Mesoscale and Nanoscale Physics · Physics 2012-02-07 K. Olejnik , J. Wunderlich , A. C. Irvine , R. P. Campion , V. P. Amin , Jairo Sinova , T. Jungwirth

The generation of spin-entangled electrons is an important prerequisite for future solid-state quantum technologies. Cooper pairs in a superconductor can be split into separate electrons in a spin-singlet state, however, detecting their…

Mesoscale and Nanoscale Physics · Physics 2021-12-23 Minh Tam , Christian Flindt , Fredrik Brange

The excellent sensitivities of quantum sensors are a double-edged sword: minuscule quantities can be observed, but any undesired signal acts as noise. This is challenging when detecting quantities that are obscured by such noise. Decoupling…

We evidence the possibility for coherent electrical manipulation of the spin orientation of topologically protected edge states in a low-symmetry quantum spin Hall insulator. By using a combination of ab-initio simulations, symmetry-based…

In order to quantify entanglement between two parts of a quantum system, one of the most used estimator is the Von Neumann entropy. Unfortunately, computing this quantity for large interacting quantum spin systems remains an open issue.…

Strongly Correlated Electrons · Physics 2011-05-26 S. Capponi , F. Alet , M. Mambrini

We report the detection of spin interference signal in an Aharonov-Bohm type interferometer with quantum dots on the conduction paths. We have found that resonators like quantum dots can work as efficient spin rotators. The interference…

Mesoscale and Nanoscale Physics · Physics 2016-08-01 Yu Iwasaki , Yoshiaki Hashimoto , Taketomo Nakamura , Shingo Katsumoto

Quantum coherence of superposed states, especially of entangled states, is indispensable for many quantum technologies. However, it is vulnerable to environmental noises, posing a fundamental challenge in solid-state systems including spin…

Electron spins in semiconductors are promising qubits because their long coherence times enable nearly 10^9 coherent quantum gate operations. However, developing a scalable high-fidelity two-qubit gate remains challenging. Here, we…

Mesoscale and Nanoscale Physics · Physics 2016-08-16 John M. Nichol , Lucas A. Orona , Shannon P. Harvey , Saeed Fallahi , Geoffrey C. Gardner , Michael J. Manfra , Amir Yacoby

We discuss the detection of entanglement in interacting quantum spin systems. First, thermodynamic Hamiltonian-based witnesses are computed for a general class of one-dimensional spin-1/2 models. Second, we introduce optimal bipartite…

Quantum Physics · Physics 2009-11-10 L. -A. Wu , S. Bandyopadhyay , M. S. Sarandy , D. A. Lidar

We demonstrate that due to their spin-orbit interaction carbon nanotube cross-junctions have attractive spin projective properties for transport. First, we show that the junction can be used as a versatile spin filter as a function of a…

Mesoscale and Nanoscale Physics · Physics 2013-11-12 Francesco Mazza , Bernd Braunecker , Patrik Recher , Alfredo Levy Yeyati

We propose a device acting as a spin valve which is based on a double quantum dot structure with parallel topology. Using the exact analytical solution for the noninteracting case we argue that, at a certain constellation of system…

Mesoscale and Nanoscale Physics · Physics 2010-03-18 J. P. Dahlhaus , S. Maier , A. Komnik