اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدSingle-qubit remote manipulation by magnetic solitons
70
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
Magnetic solitons can constitute a means for manipulating qubits from a distance. This would overcome the necessity of directly applying selective magnetic fields, which is unfeasible in the case of a matrix of qubits embedded in a solid-state quantum device. If the latter contained one-dimensional Heisenberg spin chains coupled to each qubit, one can originate a soliton in a selected chain by applying a time-dependent field at one end of it, far from the qubits. The generation of realistic solitons has been simulated. When a suitable soliton passes by, the coupled qubit undergoes nontrivial operations, even in the presence of moderate thermal noise.
قيم البحث
اقرأ أيضاً
An electromagnetic field quadrature measurement, performed on one of the modes of the nonlocal single-photon state $a|1,0>-b|0,1>$, collapses it into a superposition of the single-photon and vacuum states in the other mode. We use this effect to impl
ement remote preparation of arbitrary single-mode photonic qubits conditioned on observation of a preselected quadrature value. The quantum efficiency of the prepared qubit can be higher than that of the initial single photon.
We examine the entanglement between two qubits, supposed to be remotely located and driven by independent quantized optical fields. No interaction is allowed between the qubits, but their degree of entanglement changes as a function of time. We repor
t a collapse and revival of entanglement that is similar to the collapse and revival of single-atom properties in cavity QED.
A qubit chosen from equatorial or polar great circles on a Bloch sphere can be remotely prepared with an Einstain-Podolsky-Rosen (EPR) state shared and a cbit communication. We generalize this protocal into an arbitrary longitudinal qubit on the Bloc
h sphere in which the azimuthal angle phi can be an arbitrary value instead of only being zero. The generalized scheme was experimentally realized using liquid-state nuclear magnetic resonance (NMR) techniques. Also, we have experimentally demonstrated remote state measurement (RSM) on an arbitary qubit proposed by Pati.
We consider a scenario of remote state preparation of qubits where a single copy of an entangled state is shared between Alice and several Bobs who sequentially perform unsharp single-particle measurements. We show that a substantial number of Bobs c
an optimally and reliably prepare the qubit in Alices lab exceeding the classical realm. There can be at most 16 Bobs in a sequence when the state is chosen from the equatorial circle of the Bloch sphere. In general, depending upon the choice of a circle from the Bloch sphere, the optimum number of Bobs ranges from 12 for the worst choice, to become remarkably very large corresponding to circles in the polar regions, in case of an initially shared maximally entangled state. We further show that the bound on the number of observers successful in implementing remote state preparation is higher for maximally entangled initial states than that for non-maximally entangled initial states.
We address the dephasing dynamics of a qubit as an effective process to estimate the temperature of its environment. Our scheme is inherently quantum, since it exploits the sensitivity of the qubit to decoherence, and does not require thermalization
with the system under investigation. We optimize the quantum Fisher information with respect to the interaction time and the temperature in the case of Ohmic-like environments. We also find explicitly the qubit measurement achieving the quantum Cramer- Rao bound to precision. Our results show that the conditions for optimal estimation originate from a non-trivial interplay between the dephasing dynamics and the Ohmic structure of the environment. In general, optimal estimation is achieved neither when the qubit approaches the stationary state, nor for full dephasing.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
