Gravitational-like Potential Controls Droplet Fall Velocity Independent of Atom Number

Ultracold fluids exhibit exotic quantum behaviours, and recent research explores the properties of one-dimensional quantum droplets subjected to forces mimicking gravity, offering new avenues for precision measurement. Saurab Das, Jayanta Bera, and Ajay Nath, from the Indian Institute of Information Technology Vadodara and C. V. Raman Global University, investigate how these droplets respond to constant and changing gravitational-like potentials. Their work demonstrates that a droplet’s falling velocity depends only on the strength of this artificial gravity, regardless of its size or internal interactions, a surprising result with implications for building highly sensitive gravimeters. By analysing the droplets’ quantum properties, the researchers also reveal how even subtle changes in the applied potential affect the droplet’s coherence, potentially enabling new technologies for detecting weak gravitational fields and advancing fundamental physics.

The system incorporates a mean-field term and an attractive beyond-mean-field correction, allowing researchers to analytically characterise the quantum dots’ wavefunction within a tailored external confinement and derive the effective interaction contributions. Analogous to classical Newtonian dynamics, the falling velocity of the droplet within a finite domain depends solely on the strength of the linear gravitational-like potential, remaining independent of both the total atom number and the magnitude of internal interactions. When the linear potential is temporally modulated, deviations in the trajectory of the droplet emerge, indicating potential applicability in precision gravimetry.

Quantum Droplets and Bose-Einstein Condensate Foundations

This collection details research into quantum droplets, Bose-Einstein condensates, and related quantum phenomena, covering core concepts and theoretical foundations including the formation, properties, and dynamics of quantum droplets, which are self-bound states of matter formed in ultracold atomic gases. References also explore Bose-Einstein condensates, the foundation for quantum droplet research, and the many-body physics governing interactions between atoms in these systems. Researchers frequently employ the Gross-Pitaevskii equation to describe the dynamics of both Bose-Einstein condensates and quantum droplets, utilising computational methods for solving this equation, and some studies move beyond this approximation, exploring corrections and more sophisticated theoretical approaches. Investigations into quantum supersolidity, the coexistence of superfluidity and crystalline order, and studies of solitons and bright solitons, localized waves often appearing as precursors to quantum droplet formation, are also prominent.

Studies examine the role of quantum fluctuations in driving the crossover from a dilute Bose-Einstein condensate to a macroscopic droplet, and researchers investigate collective excitations, the vibrational and other collective modes of quantum droplets, and their behaviour at finite temperatures. Optical lattices and periodic potentials are used to confine and manipulate quantum droplets, creating novel quantum states, while explorations into quasi-periodic confinement and driven systems expand the range of accessible phenomena. The research employs tools such as Shannon entropy and the Wigner function to characterise the quantum state and uncertainty in these systems, utilising phase space analysis to understand dynamics and stability. Computational methods are central to solving the relevant equations, with some studies providing Fortran programs for time-dependent calculations.

The work extends to matter-wave solitons and patterns, exploring the creation and control of these phenomena, and investigates connections between quantum droplets and time crystals, systems exhibiting periodic behaviour in time. Potential applications in quantum sensing and quantum information processing are also explored, reflecting a highly interdisciplinary field drawing on atomic physics, condensed matter physics, quantum optics, and computational physics. The large number of references indicates that quantum droplets are a very active area of research with new discoveries being made regularly, suggesting potential applications in quantum technologies, such as quantum sensing and quantum computing.

Ultradilute Droplet Dynamics in Artificial Gravity

Researchers have developed a detailed theoretical understanding of ultradilute quantum droplets when subjected to forces mimicking gravity. These droplets, created in a carefully balanced binary Bose-Einstein condensate, exhibit unique properties due to the interplay between repulsive and attractive interactions between atoms. The research demonstrates how these droplets respond to both constant and time-varying gravitational-like potentials, revealing insights into their dynamics and quantum coherence. The team’s work provides an exact analytical model describing the formation and evolution of these droplets, allowing precise predictions of their behaviour.

A key finding is that the velocity at which a droplet “falls” within a confined space depends solely on the strength of the applied gravitational-like potential, remarkably independent of the total number of atoms within the droplet or the strength of internal interactions, mirroring classical Newtonian physics. Furthermore, when the applied “gravity” is modulated, detectable deviations in the droplet’s trajectory emerge, opening possibilities for highly sensitive measurements of gravitational forces. To probe the quantum nature of these droplets, researchers calculated the Wigner quasi-probability distribution, revealing intricate correlations between position and momentum. Shannon entropy analysis further demonstrated that the time-varying gravitational-like potential directly influences the droplet’s coherence. Importantly, the analytical solutions developed by the team are robust and have been confirmed through numerical simulations, suggesting promising applications in precision measurements and the exploration of fundamental physics. The ability to simulate quantum motion in curved or accelerating frames could lead to a better understanding of how external forces interact with these delicate quantum systems.

Droplet Fall Velocity Mirrors Classical Gravity

This study comprehensively investigates the behaviour of one-dimensional quantum droplets under the influence of constant and time-dependent gravitational-like potentials. Researchers analytically characterise the droplets’ wavefunctions, revealing that the falling velocity of the droplet depends solely on the strength of the applied potential, irrespective of the total atom number or the strength of interatomic interactions, a result analogous to classical Newtonian free-fall. The analysis demonstrates a clear link between external modulation parameters and droplet dynamics, providing insights into controlling these systems. Importantly, the research extends to time-varying potentials, showing that both the amplitude and frequency of modulation significantly influence the droplet’s trajectory, coherence, and localization. Shannon entropy and Wigner phase-space analyses quantify these effects, and numerical simulations confirm the stability of the analytical solutions even with added perturbations. These findings have implications for simulating gravitational effects and developing microgravity analogs using ultracold atomic systems, with potential applications in quantum sensing, interferometry, and precision gravimetry.