152 citations · 868 across the 65 of their papers we have counts for
16 papers · 1 filter
Virtual temperatures as a key quantifier for passive states in quantum thermodynamic processes
Sachin Sonkar, Ramandeep S. Johal
We analyze the role of virtual temperatures for passive quantum states through the lens of majorization theory. A mean temperature over the virtual temperatures of adjacent energy…
Ergotropic advantage in a measurement-fueled quantum heat engine
Sidhant Jakhar, Ramandeep S. Johal
This paper investigates a coupled two-qubits heat engine fueled by generalized measurements of the spin components and using a single heat reservoir as sink. Our model extends the…
Energy-gap modulation and majorization in three-level quantum Otto engine
Sachin Sonkar, Ramandeep S. Johal
A three-level quantum system having two energy gaps presents a nontrivial working medium for a quantum heat engine. Our focus lies in understanding the constraints on the ability t…
Spins-based Quantum Otto Engines and Majorisation
Sachin Sonkar, Ramandeep S. Johal
The concept of majorisation is explored as a tool to characterize the performance of a quantum Otto engine in the quasi-static regime. For a working substance in the form of a spin…
Quantum heat engines with complex working media, complete Otto cycles and heuristics
Venu Mehta, Ramandeep S. Johal
Quantum thermal machines make use of non-classical thermodynamic resources, one of which is interactions between elements of the quantum working medium. In this paper, we examine t…
Three-level laser heat engine at optimal performance with ecological function
Varinder Singh, Ramandeep S. Johal
Although classical and quantum heat engines work on entirely different fundamental principles, there is an underlying similarity. For instance, the form of efficiency at optimal pe…
Friction due to inhomogeneous driving of coupled spins in a quantum heat engine
George Thomas, Ramandeep S. Johal
We consider two spin-1/2 particles with isotropic Heisenberg interaction, as the working substance of a quantum heat engine. We observe a frictional effect on the adiabatic branche…
Expected Behavior of Quantum Thermodynamic Machines with Prior Information
George Thomas, Ramandeep S. Johal
We estimate the expected behavior of a quantum model of heat engine when we have incomplete information about external macroscopic parameters, like magnetic field controlling the i…
A Coupled Quantum Otto Cycle
George Thomas, Ramandeep S. Johal
We study the 1-d isotropic Heisenberg model of two spin-1/2 systems as a quantum heat engine. The engine undergoes a four-step Otto cycle where the two adiabatic branches involve c…
Quantum heat engines and nonequilibrium temperature
Ramandeep S. Johal
A pair of two-level systems initially prepared in different thermal states and coupled to an external reversible work source, do not in general reach a common temperature at the en…
On matrix elements of phase-angular momentum commutator in Hilbert space of arbitrary dimensions
Ramandeep S. Johal
We discuss correspondence between the predictions of quantum theories for rotation angle formulated in infinite and finite dimensional Hilbert spaces, taking as example, the calcul…
Dynamics with unitary phase operator:implications for Wigner's problem
Ramandeep S. Johal
We show that for general deformations of SU(2) algebra, the dynamics in terms of ladder operators is preserved. This is done for a system of precessing magnetic dipole in magnetic…
q-deformed dynamics and Josephson junction
Ramandeep S. Johal
We define a generalized rate equation for an observable in quantum mechanics, that involves a parameter q and whose limit gives the standard Heisenberg equation. The gener…
Phase shift operator and cyclic evolution in finite dimensional Hilbert space
Ramandeep S. Johal
We address the problem of phase shift operator acting as time evolution operator in Pegg-Barnett formalism. It is argued that standard shift operator is inconsistent with the behav…
Is the Deformation Parameter in q-Rotor Model Really Phenomenological ?
Ramandeep S. Johal
We cast the -rotor in the framework of Barnett-Pegg theory for rotation angle, whose underlying algebra is . A new method to fix the deformation parameter from the theo…
Angular Velocity Operator and Barnett-Pegg Formalism
Ramandeep S. Johal
We define a new operator within Barnett-Pegg formalism for phase angle. The physical predictions for this operator correspond to those expected of an angular velocity operator. Exa…