Javier Contreras

Prof. Javier Contreras


Research Focus & Metrics

Academic Career Length

4Years (2023-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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20 October 2023 in Photonics
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Journal Article
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JCJavier Contreras
Javier Contreras
FCFray de Landa Castillo-Alvarado
Fray de Landa Castillo-Alvarado
JPJosé Luis Hernandez Pozos
José Luis Hernandez Pozos
We present a scheme, based on Bloch equations and Zeno-type measurements, that allows the control of the probability density evolution of the eigenstates of a V-type system. The equations are solved numerically and we present how the population in each level can be controlled using different sequences of “pulse measurements”. The entropy between the “measurement device” and the field used to perform the measurement process is evaluated for different strengths of such field, these calculations show that the entropy is maximized when we are in the Zeno regime. The results shown here unveil different possible strategies for controlling the population levels of a V-type system and could be implemented, for example, in trapped ions or RMN qubits.

18 December 2025 in Entropy
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Journal Article
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RPRicardo Páez-Hernández
Ricardo Páez-Hernández
JPJuan Carlos Pacheco Paez
Juan Carlos Pacheco Paez
JCJuan Carlos Chimal-Eguía
Juan Carlos Chimal-Eguía
DLDelfino Ladino-Luna
Delfino Ladino-Luna
JCJavier Contreras
Javier Contreras
This work extends the steady flow Lenoir cycle within finite-time thermodynamics (FTT) by incorporating heat transfer irreversibilities through the ε−NTU formalism and a non-isentropic expansion modeled via the expander isentropic efficiency ηE. The total conductance UT (sum for the two heat exchangers) is partitioned between hot and cold units using uL=UL/UT, with UT=UH+UL. For each triplet (τ=TH/TL, UL, UT), we closed the cycle by determining T1, the working fluid temperature at the cooler outlet and heater inlet, T2, the heater outlet and expander inlet, and T3, the expander outlet and cooler inlet. Using these states, we compute the heat rates Q˙12, Q˙31 and the net power P. In addition to the thermal efficiency η, the following extended objective functions are evaluated: the efficient power EF, the ecological efficiency ϕ, and the second law efficiency ηII. Parametric sweeps on uL for τ ϵ 3.25,3.75 and UT ϵ 2.5,5.0,7.5,10 kW show unimodal curves for P(uL) and maxima. A robust result places the optima of P, η, EF, ϕ, and ηII in a distribution band at uL~0.6. This guideline offers clear design guidance for allocating exchange area in heat recovery and microgeneration, maximizing power, high η, and exergetic utilization with contained entropic penalty.