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Aravind P. Babu

Publications and source records attributed to Aravind P. Babu.

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Simulating the Dicke Model on Qubit-Based and hybrid Qubit-Boson-Based Quantum Computers

The Dicke model provides a fundamental description of collective light-matter interactions and has long served as a testbed for exploring a wide range of physical phenomena in quantum optics and condensed matter physics. In this work, we develop a variational framework for investigating the finite-size Dicke model on both fully qubit-based (digital) and hybrid qubit boson based (digital-analogue) quantum computing platforms. We show that the resulting model reproduces the characteristic critical behavior of the Dicke model in the appropriate large-spin limit while remaining suitable for implementation on both classical emulators of quantum computers and actual trapped ion quantum computers, albeit in the case of latter somewhat limited by noise. Finally, we introduce a complementary hybrid qubit-bosonic variational ansatz that directly exploits the bosonic degree of freedom to reduce quantum resources and discuss its potential implementation on hybrid quantum hardware. Our results establish a scalable, symmetry-aware framework for variational quantum simulations of collective light-matter systems and provide a pathway toward efficient simulations of more general spin-boson models on near-term quantum devices.

quant-ph

Van der Waal's gas equation for an adiabatic process and its Carnot engine efficiency

There has been many studies on gases which obeys Van der Waal's equation of state. However there is no specific and direct studies of Van der Waal's gas which undergoes adiabatic processes are available in the undergraduate text books and also in literature. In an adiabatic process there is no heat energy exchange between the system and its surroundings. In this article, we find that the Van der Waal's equation for the adiabatic process as $\left(P+\frac{n^2a}{V^2}\right) \left(V-nb\right)^Γ=\mbox{constant}$, where $P$ is the pressure, $V$ is the volume, $n$ is the number of moles of the Van der Waal's gas, $a$ and $b$ are Van der Waal's constant and $Γ$ is a factor which relates the specific heat at constant pressure and at constant volume. We use this relation explicitly and obtained the efficiency of a Carnot engine whose working substance obeys Van der Waal's equation of state. Our simplest approach may provide clear idea to the undergraduate students that $Γ$ is different from $γ$ of the ideal gas for an adiabatic process. We also shown that the efficiency of the Carnot engine is independent of the working substance.

cond-mat.stat-mech