اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدConclusive Identification of Quantum Channels via Monogamy of Quantum Correlations
125
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We investigate the action of local and global noise on monogamy of quantum correlations, when monogamy scores are considered as observables, and three-qubit systems are subjected to global noise and various local noisy channels, namely, amplitude-damping, phase-damping, and depolarizing channels. We show that the dynamics of monogamy scores corresponding to negativity and quantum discord, in the case of generalized W states, as inputs to the noisy channels, can exhibit non-monotonic dynamics with respect to increasing noise parameter, which is in contrast to the monotonic decay of monogamy scores when generalized Greenberger-Horne-Zeilinger states are exposed to noise. We quantify the persistence of monogamy against noise via a characteristic value of the noise parameter, and show that depolarizing noise destroys monogamy of quantum correlation faster compared to other noisy channels. We demonstrate that the negativity monogamy score is more robust than the quantum discord monogamy score, when the noise is of the phase-damping type. We also investigate the variation of monogamy with increasing noise for arbitrary three-qubit pure states as inputs. Finally, depending on these results, we propose a two-step protocol, which can conclusively identify the type of noise applied to the quantum system, by using generalized Greenberger-Horne-Zeilinger and generalized W states as resource states. We discuss a possible generalization of the results to higher number of parties.
قيم البحث
اقرأ أيضاً
Markovianity lies at the heart of classical communication problems. This in turn makes the information-theoretic characterization of Markovian processes worthwhile. Data processing inequalities are ubiquitous in this sense, assigning necessary condit
ions for all Markovian processes. We address here the problem of the information-theoretic analysis of constraints on Markovian processes in the quantum regime. Firstly, we show the existence of a novel class of quantum data processing inequalities called here quantum Markov monogamy inequalities. This new class of necessary conditions on quantum Markovian processes is inspired by its counterpart for classical Markovian processes, and thus providing a strong link between classical and quantum constraints on Markovianity. Secondly, we show the relevance of such inequalities by considering an example of non-Markovian behaviour witnessed by a monogamy inequality, nevertheless, do not violating any of the remaining data processing inequalities. Lastly, we show how this inequalities can be used to witness non-Markovianity at the level of the process tensor formalism.
We aim to devise feasible, efficient verification schemes for bosonic channels. To this end, we construct an average-fidelity witness that yields a tight lower bound for average fidelity plus a general framework for verifying optimal quantum channels
. For both multi-mode unitary Gaussian channels and single-mode amplification channels, we present experimentally feasible average-fidelity witnesses and reliable verification schemes, for which sample complexity scales polynomially with respect to all channel specification parameters. Our verification scheme provides an approach to benchmark the performance of bosonic channels on a set of Gaussian-distributed coherent states by employing only two-mode squeezed vacuum states and local homodyne detections. Our results demonstrate how to perform feasible tests of quantum components designed for continuous-variable quantum information processing.
As with classical information, error-correcting codes enable reliable transmission of quantum information through noisy or lossy channels. In contrast to the classical theory, imperfect quantum channels exhibit a strong kind of synergy: there exist p
airs of discrete memoryless quantum channels, each of zero quantum capacity, which acquire positive quantum capacity when used together. Here we show that this superactivation phenomenon also occurs in the more realistic setting of optical channels with attenuation and Gaussian noise. This paves the way for its experimental realization and application in real-world communications systems.
Time-domain interferometry (TDI) is a method to probe space-time correlations among particles in condensed matter systems. Applying TDI to quantum systems raises the general question, whether two-time correlations can be reliably measured without adv
erse impact of the measurement backaction onto the dynamics of the system. Here, we show that a recently developed quantum version of TDI (QTDI) indeed can access the full quantum-mechanical two-time correlations without backaction. We further generalize QTDI to weak classical continuous-mode coherent input states, alleviating the need for single-photon input fields. Finally, we interpret our results by splitting the space-time correlations into two parts. While the first one is associated to projective measurements and thus insensitive to backaction, we identify the second contribution as arising from the coherence properties of the state of the probed target system, such that it is perturbed or even destroyed by measurements on the system.
Quantum coherence plays an important role in quantum information protocols that provide an advantage over classical information processing. The amount of coherence that can exist between two orthogonal subspaces is limited by the positivity constrain
t on the density matrix. On the level of multipartite systems, this gives rise to what is known as monogamy of entanglement. On the level of single systems this leads to a bound, and hence, a trade-off in coherence that can exist between different orthogonal subspaces. In this work we derive trade-off relations for the amount of coherence that can be shared between a given subspace and all other subspaces based on trace norm, Hilbert-Schmidt norm and von Neumann relative entropy. From this we derive criteria detecting genuine multisubspace coherence.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
