Energy cost of creating quantum coherence

Misra, Avijit; Singh, Uttam; Bhattacharya, Samyadeb; Pati, Arun Kumar

doi:10.1103/physreva.93.052335

Cited by 86 publications

(71 citation statements)

References 68 publications

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“…First, since the issue discussed in this work can also be regarded as a coherence-creating problem, the method raised in Ref. [44] is a particular case of Theorem 1, by noting that the basis {|φ j } used to construct the optimal unitary operation is just induced by the Fourier matrix…”

Section: Discussionmentioning

confidence: 99%

Maximal coherence in a generic basis

Yao

Dong

et al. 2016

Phys. Rev. A

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Since quantum coherence is an undoubted characteristic trait of quantum physics, the quantification and application of quantum coherence has been one of the long-standing central topics in quantum information science. Within the framework of a resource theory of quantum coherence proposed recently, a fiducial basis should be pre-selected for characterizing the quantum coherence in specific circumstances, namely, the quantum coherence is a basis-dependent quantity. Therefore, a natural question is raised: what are the maximum and minimum coherences contained in a certain quantum state with respect to a generic basis? While the minimum case is trivial, it is not so intuitive to verify in which basis the quantum coherence is maximal. Based on the coherence measure of relative entropy, we indicate the particular basis in which the quantum coherence is maximal for a given state, where the Fourier matrix (or more generally, complex Hadamard matrices) plays a critical role in determining the basis. Intriguingly, though we can prove that the basis associated with the Fourier matrix is a stationary point for optimizing the l 1 norm of coherence, numerical simulation shows that it is not a global optimal choice.

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Section: Discussionmentioning

confidence: 99%

Maximal coherence in a generic basis

Yao

Dong

et al. 2016

Phys. Rev. A

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“…Naturally, the extraction of work from non-passive quantum states using arbitrary unitaries has therefore been the subject of many fruitful investigations (see, e.g., [10][11][12][13]). This has provided useful insights into the role of coherence, correlations, and entanglement for work extraction [14][15][16][17], and conversely, about the work cost for establishing correlations [18][19][20] and coherence [21].…”

Section: Introductionmentioning

confidence: 99%

Passivity and practical work extraction using Gaussian operations

Brown¹,

Friis²,

Huber³

2016

New J. Phys.

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Quantum states that can yield work in a cyclical Hamiltonian process form one of the primary resources in the context of quantum thermodynamics. Conversely, states whose average energy cannot be lowered by unitary transformations are called passive. However, while work may be extracted from non-passive states using arbitrary unitaries, the latter may be hard to realize in practice. It is therefore pertinent to consider the passivity of states under restricted classes of operations that can be feasibly implemented. Here, we ask how restrictive the class of Gaussian unitaries is for the task of work extraction. We investigate the notion of Gaussian passivity, that is, we present necessary and sufficient criteria identifying all states whose energy cannot be lowered by Gaussian unitaries. For all other states we give a prescription for the Gaussian operations that extract the maximal amount of energy. Finally, we show that the gap between passivity and Gaussian passivity is maximal, i.e., Gaussian-passive states may still have a maximal amount of energy that is extractable by arbitrary unitaries, even under entropy constraints.

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“…As mentioned in the introduction, the l 1 -norm and the REOC satisfy the conditions for being quantifiers of coherence [2]. These two measures have turned out to be the most frequently used when analyzing coherence in different processes (see, e.g., [17,42]). In this study, we use both l 1 -norm and REOC, in order to cover both geometric and entropic aspects of coherence.…”

Section: Quantifying Coherencementioning

confidence: 99%

“…There are different processes where quantum coherence has been shown to enhance the outcome in some aspect, i.e., function as a resource. Examples can be found in quantum thermodynamics [14][15][16][17][18] and photocells [19,20]. A mechanism for which the importance of quantum coherence has been widely discussed and studied over the last years is excitation energy transfer (EET) in photosynthetic complexes.…”

Section: Introductionmentioning

confidence: 99%

The role of quantum coherence in dimer and trimer excitation energy transfer

Bengtson

Sjöqvist

2017

New J. Phys.

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Recent progress in resource theory of quantum coherence has resulted in measures to quantify coherence in quantum systems. Especially, the l 1 -norm and relative entropy of coherence have been shown to be proper quantifiers of coherence and have been used to investigate coherence properties in different operational tasks. Since long-lasting quantum coherence has been experimentally confirmed in a number of photosynthetic complexes, it has been debated if and how coherence is connected to the known efficiency of population transfer in such systems. In this study, we investigate quantitatively the relationship between coherence, as quantified by l 1 -norm and relative entropy of coherence, and efficiency, as quantified by fidelity, for population transfer between end-sites in a network of two-level quantum systems. In particular, we use the coherence averaged over the duration of the population transfer in order to carry out a quantitative comparison between coherence and fidelity. Our results show that although coherence is a necessary requirement for population transfer, there is no unique relation between coherence and the efficiency of the transfer process.

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Energy cost of creating quantum coherence

Cited by 86 publications

References 68 publications

Maximal coherence in a generic basis

Maximal coherence in a generic basis

Passivity and practical work extraction using Gaussian operations

The role of quantum coherence in dimer and trimer excitation energy transfer

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