arXiv subjects

Madan Mohan Mahana

Publications and source records attributed to Madan Mohan Mahana.

5 recordsLinked to original sources

arXiv2026

Squeezing enhanced homodyne weak force sensing in cavity optomechanics

Cavity optomechanical systems have emerged as a promising platform for quantum sensing. Quantum mechanics imposes a standard quantum limit (SQL) on the force-sensitivity for the standard homodyne phase quadrature measurement of the cavity's output field. In this paper, we investigate ways to enhance weak force sensitivity beyond SQL by employing a variational homodyne quadrature readout and quantum squeezing. Our study reveals a remarkable improvement in the force sensitivity of a cavity optomechanical sensor at a suitable homodyne angle, compared with standard phase quadrature detection of the cavity output field within a specific frequency band. We further demonstrate improved force sensitivity via intra-cavity squeezing (ICS) or injected external squeezing (IES) of the cavity mode. Both variational homodyne readout and quantum squeezing induce quantum correlations between the amplitude and phase quadratures of the cavity's output field, thereby improving force sensitivity. Our results suggest that IES is preferable to ICS for sub-SQL force sensing with system stability and lower probe power requirements. The squeezing-enhanced variational homodyne detection scheme can enable high-precision quantum sensing across various hybrid quantum platforms.

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arXiv2026

Coherent Control of Population and Quantum Coherence in Superconducting Circuits

Quantum mechanics, with its counterintuitive principles and probabilistic nature, has long been confined to the microscopic realm of atoms and photons. Yet, recent breakthroughs have pushed the boundaries of quantum behavior into the macroscopic world, where objects are visible to the naked eye and governed by classical physics. This review article traces the extraordinary progress toward achieving coherent control of population distributions among multiple quantum levels, as well as manipulation of absorption and refractive index, in such large-scale quantum systems, a feat once considered beyond reach.

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arXiv2025

Unconventional photon blockade in cavity QED with parametric amplification

We theoretically investigate the quantum-interference-induced photon blockade effect in a single two-level atom-cavity quantum electrodynamics (QED) system with degenerate parametric amplification. The analytical calculations reveal the optimal parametric gain and phase parameters for achieving optimum unconventional photon blockade conditions. Under the optimal parameter regime, the numerical results of the second-order correlation function demonstrate strong photon antibunching consistent with the analytical results. Furthermore, the numerical results corroborate that coherently driving the atom leads to a stronger photon blockade than a coherently driven cavity with the optimal parameters. We numerically demonstrate that the UPB effect is compromised by a non-zero cavity-atom coupling in the cavity-driven configuration. However, stronger photon antibunching can be attained with a non-zero cavity-atom coupling in the atom-driven configuration. This work may be suitable for experimentally realising a strongly antibunched single-photon source for applications in quantum technology.

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arXiv2025

Controllable Single Photon Scattering via Coupling of Driven $Λ$ System with Topological Waveguide

We investigate the coherent single photon scattering process in a topological waveguide coupled with a driven $Λ$ system. We derive an analytical expression for transmittance by using the scattering formalism for three different sublattice sites (A, B, and AB), which couples to the $Λ$ system. We have demonstrated that the system's response is topology-independent for A and B sublattice-site coupling and becomes topology-dependent for AB sublattice-site coupling. In a weak control field regime, the system behaves as a perfect mirror in all of these configurations. Upon the control field strength enhancement, the transmission spectrum evolves from Electromagnetically Induced Transparency (EIT) to Autler-Townes splitting (ATS) in A and B sublattice-site coupling. The manipulation of transmission from opaque to transparent holds the key mechanism of a single photon switch. Further, the topology-dependent AB sublattice configuration allows the sharper Fano line shape that is absent in topology-independent A and B sublattice configurations. This characteristic of the Fano line can be used as a tunable single-photon switch and for sensing external perturbations. Furthermore, our study paves the way for the robustness and tunability of systems with applications in quantum technologies such as quantum switches, sensors, and communication devices.

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arXiv2023

Coherent population transfer with polariton states in circuit QED

This article proposes a new method to increase the efficiency of stimulated Raman adiabatic passage (STIRAP) in superconducting circuits using a shortcut to the adiabaticity (STA) method. The STA speeds up the adiabatic process before decoherence has a significant effect, thus leading to increased efficiency. This method achieves fast, high-fidelity coherent population transfer, known as super-adiabatic STIRAP (saSTIRAP), in a dressed state-engineered $Λ$ system with polariton states in circuit QED.

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