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Many-body entangled quantum spin systems exhibit emergent phenomena such as topological quantum spin liquids with distinct excitation spectra accessed in inelastic neutron scattering (INS) experiments. Here we simulate the dynamics of a…

We present a scheme to drive a finite-dimensional quantum system into the decoherence-free subspaces(DFS) by Lyapunov control. Control fields are established by Lyapunov function. This proposal works well for both closed and open quantum…

Quantum Physics · Physics 2013-05-29 X. X. Yi , X. L. Huang , Chunfeng Wu , C. H. Oh

We present the implementation of spinor quantum transport within the non-equilibrium Green's function (NEGF) code TranSIESTA based on Density Functional Theory (DFT). First-principles methods play an essential role in molecular and material…

Mesoscale and Nanoscale Physics · Physics 2025-06-02 Nils Wittemeier , Nick Papior , Mads Brandbyge , Zeila Zanolli , Pablo Ordejón

The undesired interaction of a quantum system with its environment generally leads to a coherence decay of superposition states in time. A precise knowledge of the spectral content of the noise induced by the environment is crucial to…

Dynamical decoupling (DD) is a popular technique for protecting qubits from the environment. However, unless special care is taken, experimental errors in the control pulses used in this technique can destroy the quantum information instead…

Quantum Physics · Physics 2011-06-20 Alexandre M. Souza , Gonzalo A. Alvarez , Dieter Suter

We discuss the operational definition of decoherence in various solid state systems. In particular, we review, in the context of spin-based solid state quantum computation, the introduction of $T_1$ and $T_2$ to describe decoherence in a…

Mesoscale and Nanoscale Physics · Physics 2017-08-23 Xuedong Hu , Rogerio de Sousa , S. Das Sarma

Si-MOS based QD qubits are attractive due to their similarity to the current semiconductor industry. We introduce a highly tunable MOS foundry compatible qubit design that couples an electrostatic quantum dot (QD) with an implanted donor.…

Mesoscale and Nanoscale Physics · Physics 2018-02-13 M. Rudolph , P. Harvey-Collard , R. Jock , N. T. Jacobson , J. Wendt , T. Pluym , J. Dominguez , G. Ten-Eyck , R. Manginell , M. P. Lilly , M. S. Carroll

We analyze decoherence-free (DF) quantum information in the presence of an arbitrary non-nearest-neighbor bath-induced system Hamiltonian using a Markovian master equation. We show that the most appropriate encoding for N qubits is probably…

Quantum Physics · Physics 2008-06-25 Peter G. Brooke , James D. Cresser , Manas K. Patra

We analyze a quantum computer (QC) design based on nuclear spin qubits in a quasi-one-dimensional (1D) chain of non-Kramers doublet atoms. We explore the use of spatial symmetry breaking to obtain control over the local dynamics of a qubit.…

Other Condensed Matter · Physics 2009-11-10 E. Novais , A. H. Castro Neto

Quantum computers must be able to function in the presence of decoherence. The simplest strategy for decoherence reduction is dynamical decoupling (DD), which requires no encoding overhead and works by converting quantum gates into…

Quantum Physics · Physics 2018-12-05 Bibek Pokharel , Namit Anand , Benjamin Fortman , Daniel Lidar

Protecting quantum states from the decohering effects of the environment is of great importance for the development of quantum computation devices and quantum simulators. Here, we introduce a continuous dynamical decoupling protocol that…

Quantum Physics · Physics 2019-04-10 İ. Yalçınkaya , B. Çakmak , G. Karpat , F. F. Fanchini

Quantum bit or qubit is a two-level system, which builds the foundation for quantum computation, simulation, communication and sensing. Quantum states of higher dimension, i.e., qutrits (D = 3) and especially qudits (D = 4 or higher), offer…

Artificial magnetic molecules are suitable hosts to one or several spin qubits, which could then implement small-scale algorithms. In order to become of practical use, such molecular spin processors need to increase the dimension $d$ of the…

Aperiodic dynamical decoupling (DD) sequences of $\pi$ pulses are of great interest to decoherence control and have been recently extended from single-qubit to two-qubit systems. If the environmental noise power spectrum is made available,…

Quantum Physics · Physics 2011-10-25 Yu Pan , Zai-Rong Xi , Jiangbin Gong

We study dynamical spin structure factor (DSSF) of S = 1/2 Heisenberg model on the kagome lattice (KAFM) by means of density-matrix renormalization group. By comparison with the well-defined magnetic ordered state and chiral spin liquid…

Strongly Correlated Electrons · Physics 2019-05-22 W. Zhu , Shou-Shu Gong , D. N. Sheng

The implementation of large-scale fault-tolerant quantum computers calls for the integration of millions of physical qubits, with error rates of physical qubits significantly below 1%. This outstanding engineering challenge may benefit from…

Mesoscale and Nanoscale Physics · Physics 2021-12-30 Jeroen Danon , Anasua Chatterjee , András Gyenis , Ferdinand Kuemmeth

We review recent advances on the theory of spin qubits in nanostructures. We focus on four selected topics. First, we show how to form spin qubits in the new and promising material graphene. Afterwards, we discuss spin relaxation and…

Mesoscale and Nanoscale Physics · Physics 2008-08-29 B. Trauzettel , M. Borhani , M. Trif , D. Loss

Exact results for the dynamic dimer and trimer structure factors of the one-dimensional s=1/2 XX model in a transverse magnetic field ($\parallel z$) are presented and discussed in relation to known exact results for the dynamic spin…

Statistical Mechanics · Physics 2016-08-16 Oleg Derzhko , Taras Krokhmalskii , Joachim Stolze , Gerhard Müller

Fluorescent spin qubits are central building blocks of quantum technologies. Placing these qubits at surfaces maximizes coupling to nearby spins and fields, enabling nanoscale sensing and facilitating integration with photonic and…

We consider a class of 6D superconformal field theories (SCFTs) which have a large $N$ limit and a semi-classical gravity dual description. Using the quiver-like structure of 6D SCFTs we study a subsector of operators protected from large…

High Energy Physics - Theory · Physics 2020-11-19 Jonathan J. Heckman