Information Phonons in Quantum Liquids (IPQL)

In many-body quantum systems, the elementary excitations that carry energy and momentum are usually understood as phonons, rotons, or other well‑studied quasi‑particles. In this work we propose a new class of collective excitations, termed information phonons, that exist in quantum liquids. Unlike conventional phonons, an information phonon is defined by a field operator φ_I that carries an additional degree of freedom encoding classical or quantum information. We construct a minimal model Hamiltonian that describes the coupling between the density fluctuations of the liquid and the information field, derive the dispersion relation for φ_I, and analyze its properties. Theoretical analysis shows that the information phonon can propagate with a velocity distinct from the sound velocity, possesses a non‑trivial topological structure, and can be manipulated by external fields. We discuss the implications of these excitations for quantum information processing, suggesting that IPQLs could provide a new platform for robust quantum memories and information transport in strongly correlated media. The discovery of such quasi‑particles opens a promising avenue toward realizing novel quantum technologies and deepening our understanding of emergent phenomena in quantum liquids.In many-body quantum systems, the elementary excitations that carry energy and momentum are usually understood as phonons, rotons, or other well‑studied quasi‑particles. In this work we propose a new class of collective excitations, termed information phonons, that exist in quantum liquids. Unlike conventional phonons, an information phonon is defined by a field operator φ_I that carries an additional degree of freedom encoding classical or quantum information. We construct a minimal model Hamiltonian that describes the coupling between the density fluctuations of the liquid and the information field, derive the dispersion relation for φ_I, and analyze its properties. Theoretical analysis shows that the information phonon can propagate with a velocity distinct from the sound velocity, possesses a non‑trivial topological structure, and can be manipulated by external fields. We discuss the implications of these excitations for quantum information processing, suggesting that IPQLs could provide a new platform for robust quantum memories and information transport in strongly correlated media. The discovery of such quasi‑particles opens a promising avenue toward realizing novel quantum technologies and deepening our understanding of emergent phenomena in quantum liquids.

Aug 17, 20260 citations

Quantum Liquid Defect Quasiparticles (QLDQ)

Jincheng Zhang

In strongly correlated quantum liquids, topological and local defects can give rise to emergent excitations that are neither conventional phonons nor magnons. We introduce the concept of Quantum Liquid Defect Quasiparticles (QLDQ), a class of collective modes generated by the interplay of quantum fluctuations and structural imperfections. These quasiparticles, denoted $D_q$ , possess dispersion relations that mirror those of phonons but arise from the defect core rather than lattice vibrations. Using a field‑theoretical approach, we derive the effective action for a defected quantum liquid, identify the spectrum of $D_q$ modes, and analyze their statistical, topological, and thermodynamic signatures. We discuss how the presence of $D_q$ modifies the low‑temperature behavior of superfluid systems and outline potential routes to detect them in ultracold atom experiments and low‑temperature condensed‑matter platforms. The discovery of QLDQ would open a new avenue for exploring elementary excitations in quantum fluids and may have implications for quantum technologies that exploit defect‑based coherence.In strongly correlated quantum liquids, topological and local defects can give rise to emergent excitations that are neither conventional phonons nor magnons. We introduce the concept of Quantum Liquid Defect Quasiparticles (QLDQ), a class of collective modes generated by the interplay of quantum fluctuations and structural imperfections. These quasiparticles, denoted $D_q$, possess dispersion relations that mirror those of phonons but arise from the defect core rather than lattice vibrations. Using a field‑theoretical approach, we derive the effective action for a defected quantum liquid, identify the spectrum of $D_q$ modes, and analyze their statistical, topological, and thermodynamic signatures. We discuss how the presence of $D_q$ modifies the low‑temperature behavior of superfluid systems and outline potential routes to detect them in ultracold atom experiments and low‑temperature condensed‑matter platforms. The discovery of QLDQ would open a new avenue for exploring elementary excitations in quantum fluids and may have implications for quantum technologies that exploit defect‑based coherence.

Aug 17, 20260 citations

Hidden Energy Channels in Quantum Matter (HECQM)

Jincheng Zhang

In many-body quantum systems the conventional picture of energy transport assumes that excitations propagate through well‑defined quasiparticle channels governed by the system Hamiltonian. Recent theoretical investigations suggest that in strongly correlated materials there exist additional, hidden pathways for energy exchange that are not captured by standard quasiparticle descriptions. These hidden energy channels (HECs) arise from collective reconfigurations of the entanglement structure, mediated by emergent gauge fields and topological constraints. In this paper we formulate a unified framework to identify and characterize HECs in generic lattice models. We derive explicit expressions for the energy current operator that include both conventional and hidden contributions, and demonstrate how HECs modify the temperature dependence of thermal conductivity in prototypical models such as the two‑dimensional Hubbard model and the Kitaev honeycomb model. Our analysis predicts anomalous scaling laws and non‑monotonic temperature profiles that can serve as experimental signatures of HECs. The existence of these channels opens a new avenue for engineering efficient energy transport in quantum materials, with implications for quantum information processing and low‑temperature thermoelectric devices.In many-body quantum systems the conventional picture of energy transport assumes that excitations propagate through well‑defined quasiparticle channels governed by the system Hamiltonian. Recent theoretical investigations suggest that in strongly correlated materials there exist additional, hidden pathways for energy exchange that are not captured by standard quasiparticle descriptions. These hidden energy channels (HECs) arise from collective reconfigurations of the entanglement structure, mediated by emergent gauge fields and topological constraints. In this paper we formulate a unified framework to identify and characterize HECs in generic lattice models. We derive explicit expressions for the energy current operator that include both conventional and hidden contributions, and demonstrate how HECs modify the temperature dependence of thermal conductivity in prototypical models such as the two‑dimensional Hubbard model and the Kitaev honeycomb model. Our analysis predicts anomalous scaling laws and non‑monotonic temperature profiles that can serve as experimental signatures of HECs. The existence of these channels opens a new avenue for engineering efficient energy transport in quantum materials, with implications for quantum information processing and low‑temperature thermoelectric devices.

Aug 19, 20260 citations

Hidden Sound Velocity in Quantum Liquids: A Higher-Order Response Theory of Multi-Branch Collective Excitations

Jincheng Zhang

Quantum liquids, such as liquid helium and ultracold atomic gases, exhibit complex collective behaviors that traditional linear response theory fails to fully capture. In this work, we propose the theoretical framework of Hidden Sound Velocity in Quantum Liquids (HSVQL), hypothesizing the existence of multiple undiscovered collective velocities denoted as v_1, v_2, ..., v_n beyond standard propagation modes. By employing higher-order response theory, specifically analyzing the third-order susceptibility chi^(3) and nonlinear correlation functions, we demonstrate that nonlinear coupling channels reveal these hidden modes. We formulate a comprehensive hydrodynamic and microscopic theory to derive dispersion relations and quasiparticle characteristics, opening a new paradigm for uncovering novel excitations in strongly interacting many-body systems.Quantum liquids, such as liquid helium and ultracold atomic gases, exhibit complex collective behaviors that traditional linear response theory fails to fully capture. In this work, we propose the theoretical framework of Hidden Sound Velocity in Quantum Liquids (HSVQL), hypothesizing the existence of multiple undiscovered collective velocities denoted as v_1, v_2, ..., v_n beyond standard propagation modes. By employing higher-order response theory, specifically analyzing the third-order susceptibility chi^(3) and nonlinear correlation functions, we demonstrate that nonlinear coupling channels reveal these hidden modes. We formulate a comprehensive hydrodynamic and microscopic theory to derive dispersion relations and quasiparticle characteristics, opening a new paradigm for uncovering novel excitations in strongly interacting many-body systems.

Aug 13, 20260 citations

Spin-lattice coupling in U(1) quantum spin liquids

Sangjin Lee, Eun-Gook Moon

Quantum spin liquids (QSLs) are exotic phases with intrinsic massive entanglements. Instead of microscopic spins, fractionalized particles and gauge fluctuations are emergent, revealing QSLs' exotic natures. Quantum spins with strong spin-orbit coupling on a pyrochlore lattice, for example ${\mathrm{Pr}}_{2}{\mathrm{Zr}}_{2}{\mathrm{O}}_{7}$ , are suggested to host a U(1) QSL with emergent photons, gapless excitations, as well as emergent monopoles. One of the key issues in QSLs is an interplay between emergent degrees of freedom of QSLs and conventional degrees of freedom, and we investigate the interplay by constructing a general theory of spin-lattice coupling in U(1) QSLs. We find that the coupling induces characteristic interplay between phonons and photons. For example, photons become qualitatively more stable than phonons at low temperature. We also propose mechanisms to detect emergent photons in experiments such as sound attenuation and thermal transport relying on spin-lattice coupling in U(1) QSLs.Quantum spin liquids (QSLs) are exotic phases with intrinsic massive entanglements. Instead of microscopic spins, fractionalized particles and gauge fluctuations are emergent, revealing QSLs' exotic natures. Quantum spins with strong spin-orbit coupling on a pyrochlore lattice, for example ${\mathrm{Pr}}_{2}{\mathrm{Zr}}_{2}{\mathrm{O}}_{7}$, are suggested to host a U(1) QSL with emergent photons, gapless excitations, as well as emergent monopoles. One of the key issues in QSLs is an interplay between emergent degrees of freedom of QSLs and conventional degrees of freedom, and we investigate the interplay by constructing a general theory of spin-lattice coupling in U(1) QSLs. We find that the coupling induces characteristic interplay between phonons and photons. For example, photons become qualitatively more stable than phonons at low temperature. We also propose mechanisms to detect emergent photons in experiments such as sound attenuation and thermal transport relying on spin-lattice coupling in U(1) QSLs.

arXiv:1802.05280Physical review. B./Physical review. BJan 10, 20194 citations

Topological Pressure Field in Quantum Liquids

Jincheng Zhang

In many-body quantum systems at ultra‑low temperatures, the collective behavior of particles can give rise to exotic states of matter such as superfluids and quantum liquids. These states exhibit macroscopic quantum coherence and support topological excitations, yet their internal mechanical response has traditionally been described only by local thermodynamic variables such as pressure, density, and temperature. In this work we introduce the concept of a topological pressure field, denoted $P_T(x)$ , which captures the influence of non‑trivial topological order on the local mechanical pressure within a quantum liquid. The proposed field is derived from a gauge‑invariant formulation of the quantum stress tensor that incorporates Berry curvature and Chern‑Simons terms. We show that $P_T(x)$ is non‑zero only in regions where the quantum state hosts topological defects such as quantized vortices or skyrmion‑like textures. Using a simplified model of a two‑dimensional superfluid film, we calculate the spatial profile of $P_T(x)$ around a vortex core and predict measurable deviations from the classical pressure distribution. The existence of $P_T(x)$ implies that quantum liquids possess an additional mechanical degree of freedom that is purely topological. This insight opens a pathway to experimentally detect topological pressure via precision pressure sensors in superfluid helium or cold‑atom Bose‑Einstein condensates, and suggests new avenues for engineering quantum fluid devices that exploit topological mechanics.In many-body quantum systems at ultra‑low temperatures, the collective behavior of particles can give rise to exotic states of matter such as superfluids and quantum liquids. These states exhibit macroscopic quantum coherence and support topological excitations, yet their internal mechanical response has traditionally been described only by local thermodynamic variables such as pressure, density, and temperature. In this work we introduce the concept of a topological pressure field, denoted $P_T(x)$, which captures the influence of non‑trivial topological order on the local mechanical pressure within a quantum liquid. The proposed field is derived from a gauge‑invariant formulation of the quantum stress tensor that incorporates Berry curvature and Chern‑Simons terms. We show that $P_T(x)$ is non‑zero only in regions where the quantum state hosts topological defects such as quantized vortices or skyrmion‑like textures. Using a simplified model of a two‑dimensional superfluid film, we calculate the spatial profile of $P_T(x)$ around a vortex core and predict measurable deviations from the classical pressure distribution. The existence of $P_T(x)$ implies that quantum liquids possess an additional mechanical degree of freedom that is purely topological. This insight opens a pathway to experimentally detect topological pressure via precision pressure sensors in superfluid helium or cold‑atom Bose‑Einstein condensates, and suggests new avenues for engineering quantum fluid devices that exploit topological mechanics.

Aug 19, 20260 citations

D_q

, possess dispersion relations that mirror those of phonons but arise from the defect core rather than lattice vibrations. Using a field‑theoretical approach, we derive the effective action for a defected quantum liquid, identify the spectrum of

D_q

modes, and analyze their statistical, topological, and thermodynamic signatures. We discuss how the presence of

D_q

modifies the low‑temperature behavior of superfluid systems and outline potential routes to detect them in ultracold atom experiments and low‑temperature condensed‑matter platforms. The discovery of QLDQ would open a new avenue for exploring elementary excitations in quantum fluids and may have implications for quantum technologies that exploit defect‑based coherence.

{\mathrm{Pr}}_{2}{\mathrm{Zr}}_{2}{\mathrm{O}}_{7}

, are suggested to host a U(1) QSL with emergent photons, gapless excitations, as well as emergent monopoles. One of the key issues in QSLs is an interplay between emergent degrees of freedom of QSLs and conventional degrees of freedom, and we investigate the interplay by constructing a general theory of spin-lattice coupling in U(1) QSLs. We find that the coupling induces characteristic interplay between phonons and photons. For example, photons become qualitatively more stable than phonons at low temperature. We also propose mechanisms to detect emergent photons in experiments such as sound attenuation and thermal transport relying on spin-lattice coupling in U(1) QSLs.

P_T(x)

, which captures the influence of non‑trivial topological order on the local mechanical pressure within a quantum liquid. The proposed field is derived from a gauge‑invariant formulation of the quantum stress tensor that incorporates Berry curvature and Chern‑Simons terms. We show that

P_T(x)

is non‑zero only in regions where the quantum state hosts topological defects such as quantized vortices or skyrmion‑like textures. Using a simplified model of a two‑dimensional superfluid film, we calculate the spatial profile of

P_T(x)

around a vortex core and predict measurable deviations from the classical pressure distribution. The existence of

P_T(x)

implies that quantum liquids possess an additional mechanical degree of freedom that is purely topological. This insight opens a pathway to experimentally detect topological pressure via precision pressure sensors in superfluid helium or cold‑atom Bose‑Einstein condensates, and suggests new avenues for engineering quantum fluid devices that exploit topological mechanics.