Nonlinear quantum evolution does not imply supraluminal communication

Ferrero, Miguel; Salgado, David Cienfuegos; Sánchez-Gómez, J. L.

doi:10.1103/physreva.70.014101

Cited by 16 publications

(14 citation statements)

References 23 publications

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“…the disorder-induced leverage is absent for the quenched Bell inequality violation and quantum advantage in dense coding. There is an ongoing effort in conquering no-go theorems in quantum mechanics either by going beyond the static framework of the quantum formalism [24] or by relaxing quantum dynamical postulates like unitarity [25]. The work presented in this paper shows another path for overcoming the no-go theorems of ordered systems, while still remaining within the quantum realm, by introducing impurities or defects.…”

Section: Discussionmentioning

confidence: 93%

Beating no-go theorems by engineering defects in quantum spin models

Sadhukhan¹,

Roy²,

Rakshit³

et al. 2015

New J. Phys.

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Keywords: disordered quantum systems, quantum dense coding, bell inequality, No-go theorems in quantum mechanics, multiparty communication networks, monogamy in quantum mechanics Abstract Diverse no-go theorems exist, ranging from no-cloning to monogamies of quantum correlations and Bell inequality violations, which restrict the processing of information in the quantum world. In a multipartite scenario, monogamy of Bell inequality violation and the exclusion principle of dense coding are such theorems which impede the ability of the system to have quantum advantage between all its parts. In ordered spin systems, the twin restrictions of translation invariance and monogamy of quantum correlations, in general, enforce the bipartite states to be neither Bell inequality violating nor dense codeable. We show that it is possible to conquer these constraints imposed by quantum mechanics in ordered systems by introducing quenched impurities in the system while still retaining translation invariance at the physically relevant level of disorder-averaged observables.

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Section: Discussionmentioning

confidence: 93%

Beating no-go theorems by engineering defects in quantum spin models

Sadhukhan¹,

Roy²,

Rakshit³

et al. 2015

New J. Phys.

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“…Although there is no conclusive empirical evidence to prove these theories right or wrong, there is some empirical evidence, as seen, for example, in Sections 3.2 and 3.3 above, to at least suggest that one of these approaches, i.e., IQT, may indeed be a reasonable physical explanation for the phenomena of decoherence and decorrelation recently experimentally reported at a microscopic level [106][107][108][109][110][111][112][113]116]. Furthermore, although the validity of the ansatz of a fundamental nonlinearity at the quantum level of description has often been criticized as incompatible with the so-called "no-signaling condition", recent work by Ferreo, Salgado, and Sánchez-Gómez [132] suggests that nonlinear quantum evolution is in principle perfectly compatible with the impossibility of supraluminal communication, thus, reopening the discussion of fundamental non-linearity from this standpoint as well. Nonetheless, these theories remain controversial and not widely accepted even though in a number of instances their mathematical and geometrical formulations have begun to provide new, powerful, and effective modeling tools for reactive and non-reactive systems as demonstrated, for example, by the applications above of the SEA-QT framework to a number of diverse systems and phenomena (e.g., see Section 3).…”

Section: Emergent Versus Fundamental Non-linearitymentioning

confidence: 99%

Some Trends in Quantum Thermodynamics

Spakovsky

Gemmer

2014

Entropy

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Abstract:Traditional answers to what the 2nd Law is are well known. Some are based on the microstate of a system wandering rapidly through all accessible phase space, while others are based on the idea of a system occupying an initial multitude of states due to the inevitable imperfections of measurements that then effectively, in a coarse grained manner, grow in time (mixing). What has emerged are two somewhat less traditional approaches from which it is said that the 2nd Law emerges, namely, that of the theory of quantum open systems and that of the theory of typicality. These are the two principal approaches, which form the basis of what today has come to be called quantum thermodynamics. However, their dynamics remains strictly linear and unitary, and, as a number of recent publications have emphasized, "testing the unitary propagation of pure states alone cannot rule out a nonlinear propagation of mixtures". Thus, a non-traditional approach to capturing such a propagation would be one which complements the postulates of QM by the 2nd Law of thermodynamics, resulting in a possibly meaningful, nonlinear dynamics. An unorthodox approach, which does just that, is intrinsic quantum thermodynamics and its mathematical framework, steepest-entropy-ascent quantum thermodynamics. The latter has evolved into an effective tool for modeling the dynamics of reactive and non-reactive systems at atomistic scales. It is the usefulness of this framework in the context of quantum thermodynamics as well as the theory of typicality which are discussed here in some detail. A brief discussion of some other trends such as those related to work, work extraction, and fluctuation theorems is also presented. OPEN ACCESSEntropy 2014, 16 3435

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“…(24,26) In Ref. 28 we have proven that nonlinear quantum evolution does not necessarily imply the existence of supraluminal communications. This has been done by explicitly constructing some compound quantum systems with joint nonlinear evolution but whose entanglement turns out to be quite useless to exchange information.…”

Section: Information Is Physical Collapse Is a Change Of Information mentioning

confidence: 97%

“…Its alluded unavoidable implication of supraluminal communication has been recently proven to be incorrect. (28) Let us discuss this point further. One the most important consequences of the linearity of quantum mechanics (in particular, of the quantum time evolution) is the impossibility of using (spacelike) correlations to establish supraluminal communications (i.e., at velocities higher than the light and, in fact, possibly infinite) between arbitrarily far-away partners.…”

Section: Information Is Physical Collapse Is a Change Of Information mentioning

confidence: 97%

Is the Epistemic View of Quantum Mechanics Incomplete?

2004

Self Cite

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One of the most tantalizing questions about the interpretation of QuantumTheory is the objective vs. subjective meaning of quantum states. Here, by focusing on a typical EPR experiment upon which a selection procedure is performed on one side, we will confront the fully epistemic view of quantum states with its results. Our statement is that such a view cannot be considered complete, although the opposite attitude would also pose well-known problems of interpretation.

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Nonlinear quantum evolution does not imply supraluminal communication

Cited by 16 publications

References 23 publications

Beating no-go theorems by engineering defects in quantum spin models

Beating no-go theorems by engineering defects in quantum spin models

Some Trends in Quantum Thermodynamics

Is the Epistemic View of Quantum Mechanics Incomplete?

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