Quantum Carnot cycle with inner friction

Çakmak, Selçuk; Altintas, Ferdi

doi:10.1007/s11128-020-02746-x

Cited by 16 publications

(13 citation statements)

References 54 publications

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“…1 and 4, respectively. To see the possible existence of the irreversibility in a quantum system that can be experimentally achievable, we chose the parameters which are thermodynamically implemented in liquid state nuclear magnetic resonance (NMR), recently [19]. Therefore, we set the bath temperature at = 10 ⁄ and the frequency at Ω 0 = 2 here = 2 with considering the misalignment angles as {0, 5 ,…”

Section: Resultsmentioning

confidence: 99%

“…The mechanism of the system response can be explained fully with the quantum mechanical theory. The initial studies on the concept of inner friction and irreversible work are realized on various models [12][13][14][15][16][17][18][19]. The inner friction has been recently investigated in ref [14] considering misalignment and disordered samples.…”

Section: Introductionmentioning

confidence: 99%

“…The inner friction has been recently investigated in ref [14] considering misalignment and disordered samples. There have been studies that investigate the effects of inner friction on work output and the efficiency of the quantum counterpart of classical Otto and Carnot heat engines [16,19]. The finitetime driven quantum two-level system undergoing the unitary evolution shows that the quantum friction arises in the case of the fastdriven model.…”

Section: Introductionmentioning

confidence: 99%

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Quantum Irreversibility in a Misaligned Spin System

Çakmak

2021

Sakarya University Journal of Science

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A single spin that is misaligned with respect to the static external magnetic field is investigated as a toy model to clarify the nature of irreversibility in terms of inner friction and irreversible work. The coherence generation and the effects of unwanted transitions are analyzed in detail. The behavior of inner friction and irreversible work as a function of protocol time are analyzed for a finite-time unitary transformation. The coherence generation is shown to be the common sign for the inner friction and irreversible work. The excess energy sourced by the unwanted transitions for a quasistatic transformation is found to be the only sign for irreversible work. The angle dependencies of the inner friction and irreversible work are also analyzed explicitly. The selected model and the considered realistic parameters are available to be implemented for the finite-time operations on the nuclear magnetic resonance setups.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Quantum Irreversibility in a Misaligned Spin System

Çakmak

2021

Sakarya University Journal of Science

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“…This means an extra amount of energy W ir will be stored in the system, making the system state deviate from the equilibrium state and be prepared in a nonequilibrium state. This extra amount of stored energy will be released to the heat bath during the cycle's relaxation process at the beginning of the next isochoric stage [44,81]. Therefore, the net positive work output is decreased [see Eq.…”

Section: Stage 2: Expansion Stagementioning

confidence: 99%

“…Alternatively, one may also apply the so-called quantum lubrication [59] or perform shortcuts to quantum adiabaticity [19,33,[64][65][66]. Several studies attempted to determine how this internal friction affects the performance of a quantum heat engine [5,18,44,51,[58][59][60][61][62][63]67] when it operates in a finite-time cycle. During finite-duration thermodynamic processes, the system never reaches thermal equilibrium with the thermal bath and therefore sustains residual coherence in the energy eigenstate basis [63], which in turn affects the engine performance [32].…”

Section: Introductionmentioning

confidence: 99%

Finite-time performance of a single-ion quantum Otto engine

2021

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We study how a quantum heat engine based on a single trapped ion performs in finite time. The always-on thermal environment acts like the hot bath, while the motional degree of freedom of the ion plays the role of the effective cold bath. The hot isochoric stroke is implemented via the interaction of the ion with its hot environment, while a projective measurement of the internal state of the ion is performed as an equivalent to the cold isochoric stroke. The expansion and compression strokes are implemented via suitable change in applied magnetic field. We study in detail how the finite duration of each stroke affects the engine performance. We show that partial thermalization can in fact enhance the efficiency of the engine, due to the residual coherence, whereas faster expansion and compression strokes increase the inner friction and therefore reduce the efficiency.

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Quantum Machines Using Cu3$\mathrm{Cu}_{3}$‐Like Compounds Modeled by Heisenberg Antiferromagnetic in a Triangular Ring

Rojas,

Rojas

2024

Annalen der Physik

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A theoretical study of an antiferromagnetically coupled spin system, specifically , characterized by a slightly distorted equilateral triangle configuration is presented. Using the Heisenberg model with exchange and Dzyaloshinskii–Moriya interactions, g‐factors, and an external magnetic field, three quantum machines are investigated using this system as the working substance, assuming reversible processes. For the magnetocaloric effect (MCE) is significant at low temperatures (1K) under a perpendicular magnetic field (). Although only the compound is considered, since the compound behaves quite similarly. How MCE influences the Carnot machine, which operates as a heat engine or refrigerator when varying the external magnetic field is analyzed. In contrast, the Otto and Stirling machines can operate as heat engines, refrigerators, heaters, or thermal accelerators, depending on the magnetic field intensity. The results indicate that enhanced MCE broadens the operating regions for these machines, with the Otto and Stirling machines primarily functioning as refrigerators and accelerators. The corresponding thermal efficiencies are also discussed for all operating modes.

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Quantum Carnot cycle with inner friction

Cited by 16 publications

References 54 publications

Quantum Irreversibility in a Misaligned Spin System

Quantum Irreversibility in a Misaligned Spin System

Finite-time performance of a single-ion quantum Otto engine

Quantum Machines Using Cu3$\mathrm{Cu}_{3}$‐Like Compounds Modeled by Heisenberg Antiferromagnetic in a Triangular Ring

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