Fidelity of a sequence of SWAP operations on a spin chain

• URL: http://arxiv.org/abs/2004.04746v3
• Date: Mon, 27 Jul 2020 17:19:35 GMT
• Title: Fidelity of a sequence of SWAP operations on a spin chain
• Authors: Robert E. Throckmorton and S. Das Sarma
• Abstract summary: We consider the transport'' of the state of a spin across a Heisenberg-coupled spin chain via the use of repeated SWAP gates. We determine the fidelity of this sequence of operations in a number of situations. Our theory should be useful to the ongoing experimental efforts in building semiconductor-based spin quantum computer architectures.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: We consider the ``transport'' of the state of a spin across a Heisenberg-coupled spin chain via the use of repeated SWAP gates, starting with one of two states---one in which the leftmost spin is down and the others up, and one in which the leftmost two spins are in a singlet state (i.e., they are entangled), and the others are again all up. More specifically, we ``transport'' the state of the leftmost spin in the first case and the next-to-leftmost spin in the second to the other end of the chain, and then back again. We accomplish our SWAP operations here by increasing the exchange coupling between the two spins that we operate on from a base value $J$ to a larger value $J_\text{SWAP}$ for a time $t=\pi\hbar/4J_\text{SWAP}$. We determine the fidelity of this sequence of operations in a number of situations---one in which only nearest-neighbor coupling exists between spins and there is no magnetic dipole-dipole coupling or noise (the most ideal case), one in which we introduce next-nearest-neighbor coupling, but none of the other effects, and one in which all of these effects are present. In the last case, the noise is assumed to be quasistatic, i.e., the exchange couplings are each drawn from a Gaussian distribution, truncated to only nonnegative values. We plot the fidelity as a function of $J_\text{SWAP}$ to illustrate various effects, namely crosstalk due to coupling to other spins, as well as noise, that are detrimental to our ability to perform a SWAP operation. Our theory should be useful to the ongoing experimental efforts in building semiconductor-based spin quantum computer architectures.

Related papers

• An integrated neural wavefunction solver for spinful Fermi systems [41.99844472131922]
  We present an approach to solving the ground state of Fermi systems that contain spin or other discrete degrees of freedom in addition to continuous coordinates.<n>A transformer achieves both continuous position and discrete spin as inputs universal approximation to spinful generalized orbitals.<n>We validate the method on a range of two-dimensional material problems.
  arXiv  Detail & Related papers  (2025-10-21T13:20:31Z)
• Quantum Phonon Dynamics Induced Spontaneous Spin-Orbit Coupling [9.748987642024122]
  A spin-dependent electron-phonon coupling model is investigated on a half-filled square lattice. Spin-orbit coupling emerges as an order in the ground state for any $lambda$ in the adiabatic limit. Our work opens up the possibility of hidden spin-orbit coupling in materials where it is otherwise forbidden by lattice symmetry.
  arXiv  Detail & Related papers  (2024-10-22T12:19:52Z)
• Decoherence of electron spin qubit during transfer between two semiconductor quantum dots at low magnetic fields [0.0]
  Electron shuttling is one of the current avenues being pursued to scale semiconductor quantum dot-based spin qubits. We theoretically analyze the dephasing of a spin qubit that is adiabatically transferred between two tunnel-coupled quantum dots.
  arXiv  Detail & Related papers  (2024-05-20T17:13:46Z)
• Ancilla quantum measurements on interacting chains: Sensitivity of entanglement dynamics to the type and concentration of detectors [46.76612530830571]
  We consider a quantum many-body lattice system that is coupled to ancillary degrees of freedom (detectors'') We explore the dynamics of density and of entanglement entropy in the chain, for various values of $rho_a$ and $M$.
  arXiv  Detail & Related papers  (2023-11-21T21:41:11Z)
• Quantum spin chains with bond dissipation [0.26107298043931204]
  We study the effect of bond dissipation on the one-dimensional antiferromagnetic spin-$1/2$ Heisenberg model. Our results suggest that the critical properties of the dissipative system are the same as for the spin-Peierls model.
  arXiv  Detail & Related papers  (2023-10-17T18:46:27Z)
• The scaling law of the arrival time of spin systems that present pretty good transmission [49.1574468325115]
  The pretty good transmission scenario implies that the probability of sending one excitation from one extreme of a spin chain to the other can reach values arbitrarily close to the unity just by waiting a time long enough. Some works suggest that the time $t_varepsilon$ at which the pretty good transmission takes place scales as $1/(|varepsilon|)f(N)$. We show that the exponent is not a simple function of the chain length but a power law of the number of linearly independent irrational eigenvalues of the one-excitation block of the Hamiltonian
  arXiv  Detail & Related papers  (2023-09-05T13:13:00Z)
• Negative Spin $Δ_T$ noise Induced by Spin-Flip Scattering and Andreev Reflection [0.0]
  We study charge $Delta_T$ noise and spin $Delta_T$ noise in a superconducting junction.<n>While charge $Delta_T$ noise remains strictly positive, spin $Delta_T$ noise undergoes a sign reversal from positive to negative.
  arXiv  Detail & Related papers  (2023-07-26T09:48:13Z)
• Nearest-neighbor approximation in one-excitation state evolution along spin-1/2 chain governed by XX-Hamiltonian [0.0]
  approximation of nearest neighbor interaction (NNI) is widely used in short-time spin dynamics with dipole-dipole interactions (DDI) We consider the system with the intensity of the spin-spin interaction $sim 1/ralpha$, $alphage 3$, and find the low boundary $alpha_c$ of applicability of the NNI to the evolution of an arbitrary one-excitation initial quantum state in the homogeneous spin chain governed by the $XX$-Hamiltonian.
  arXiv  Detail & Related papers  (2023-01-23T15:01:12Z)
• Exact solution of a family of staggered Heisenberg chains with conclusive pretty good quantum state transfer [68.8204255655161]
  We work out the exact solutions in the one-excitation subspace. We present numerical evidence that pretty good transmission is achieved by chains whose length is not a power of two.
  arXiv  Detail & Related papers  (2022-06-28T18:31:09Z)
• Understanding the propagation of excitations in quantum spin chains with different kind of interactions [68.8204255655161]
  It is shown that the inhomogeneous chains are able to transfer excitations with near perfect fidelity. It is shown that both designed chains have in common a partially ordered spectrum and well localized eigenvectors.
  arXiv  Detail & Related papers  (2021-12-31T15:09:48Z)
• Strong-coupling emergence of dark states in XX central spin models [77.34726150561087]
  It was recently shown that the XX central spin model is integrable in the presence of a magnetic field to the plane in which the coupling exists. We show that, provided the coupling is strong enough, dark states can actually be found even in the presence of an in-plane magnetic field.
  arXiv  Detail & Related papers  (2021-12-17T15:12:02Z)
• Partitioning dysprosium's electronic spin to reveal entanglement in non-classical states [55.41644538483948]
  We report on an experimental study of entanglement in dysprosium's electronic spin. Our findings open up the possibility to engineer novel types of entangled atomic ensembles.
  arXiv  Detail & Related papers  (2021-04-29T15:02:22Z)
• Continuous dynamical decoupling of spin chains: Inducing two-qubit interactions to generate perfect entanglement [0.0]
  Control over entanglement in spin chains is useful for quantum information processing applications. We show that the quantum state of any two spins in the spin chain can be made to be a Bell state.
  arXiv  Detail & Related papers  (2020-12-07T17:36:44Z)
• Controlled quantum state transfer in $XX$ spin chains at the Quantum Speed Limit [62.997667081978825]
  In homogeneous chains it implies that taking information from one extreme of the chain to the other will take a time $O(N/2)$, where $N$ is the chain length. We design control pulses that achieve near perfect population transfer between the extremes of the chain at times on the order of $N/2$, or larger.
  arXiv  Detail & Related papers  (2020-05-15T23:10:19Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.