Pub Date : 2026-03-01Epub Date: 2026-01-29DOI: 10.1016/j.mtquan.2026.100059
Wenhao Xu (徐文昊)
Quantum synchronisation has recently been proposed as a mechanism for electronic excitation energy transfer in light-harvesting complexes, yet its robustness in driven-dissipative settings remains under active investigation. Here, we revisit this mechanism in cryptophyte photosynthetic antennae using an exciton–vibrational dimer model. By comparing the full open quantum dynamics with semi-classical rate equations for electronic density-matrix elements and vibrational observables, we demonstrate that quantum correlations between electronic and vibrational degrees of freedom, beyond the semi-classical factorised limit, underpin the emergence of quantum synchronisation. Furthermore, we introduce an environment-assisted transfer mechanism arising as a nonlinear, non-Condon correction to the dipole–dipole interaction. This mechanism enables long-lived quantum coherence and continuous, synchronisation-enhanced energy transfer in a driven-dissipative regime, thereby suggesting new avenues for investigating photosynthetic energy-transfer dynamics.
{"title":"Quantum correlation and synchronisation-enhanced energy transfer in driven-dissipative light-harvesting dimers","authors":"Wenhao Xu (徐文昊)","doi":"10.1016/j.mtquan.2026.100059","DOIUrl":"10.1016/j.mtquan.2026.100059","url":null,"abstract":"<div><div>Quantum synchronisation has recently been proposed as a mechanism for electronic excitation energy transfer in light-harvesting complexes, yet its robustness in driven-dissipative settings remains under active investigation. Here, we revisit this mechanism in cryptophyte photosynthetic antennae using an exciton–vibrational dimer model. By comparing the full open quantum dynamics with semi-classical rate equations for electronic density-matrix elements and vibrational observables, we demonstrate that quantum correlations between electronic and vibrational degrees of freedom, beyond the semi-classical factorised limit, underpin the emergence of quantum synchronisation. Furthermore, we introduce an environment-assisted transfer mechanism arising as a nonlinear, non-Condon correction to the dipole–dipole interaction. This mechanism enables long-lived quantum coherence and continuous, synchronisation-enhanced energy transfer in a driven-dissipative regime, thereby suggesting new avenues for investigating photosynthetic energy-transfer dynamics.</div></div>","PeriodicalId":100894,"journal":{"name":"Materials Today Quantum","volume":"9 ","pages":"Article 100059"},"PeriodicalIF":0.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146057390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2026-02-14DOI: 10.1016/j.mtquan.2026.100060
G.S. Gopika Krishnan, K. Muraleedharan
The optoelectronic and charge-transport characteristics of fluorene (F) and its urea derivative, N-(9H-fluoren-9-yl) urea (9FU), are investigated in this work using DFT and TD-DFT. Electronic excitations, charge extraction parameters, ionisation potentials, electron affinities, and reorganisation energies were all methodically examined. The findings demonstrate that urea substitution at fluorene's 9-position increases charge-transfer balance and electron magnetism, allowing for ambipolar behaviour. 9FU has better charge-transport and excitation properties than fluorene, suggesting that it could be used in effective OLED applications.
{"title":"Molecular insights into balanced hole and electron transport in urea-modified fluorene for OLED applications","authors":"G.S. Gopika Krishnan, K. Muraleedharan","doi":"10.1016/j.mtquan.2026.100060","DOIUrl":"10.1016/j.mtquan.2026.100060","url":null,"abstract":"<div><div>The optoelectronic and charge-transport characteristics of fluorene (F) and its urea derivative, N-(9H-fluoren-9-yl) urea (9FU), are investigated in this work using DFT and TD-DFT. Electronic excitations, charge extraction parameters, ionisation potentials, electron affinities, and reorganisation energies were all methodically examined. The findings demonstrate that urea substitution at fluorene's 9-position increases charge-transfer balance and electron magnetism, allowing for ambipolar behaviour. 9FU has better charge-transport and excitation properties than fluorene, suggesting that it could be used in effective OLED applications.</div></div>","PeriodicalId":100894,"journal":{"name":"Materials Today Quantum","volume":"9 ","pages":"Article 100060"},"PeriodicalIF":0.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147422957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01Epub Date: 2025-12-05DOI: 10.1016/j.mtquan.2025.100058
Juhi Singh, Narayan Mohanta
We propose an altermagnet–topological insulator bilayer as a platform to engineer Berry phase driven spin–charge responses using an interfacial buffer layer. Using a momentum-space lattice model and linear-response theory, we investigate a -wave altermagnet coupled to a topological insulator and highlight the crucial role of spin-flip tunneling in shaping its electronic and transport properties. Interfacial hybridization strongly modifies the band structure, leading to anisotropic Rashba–Edelstein and Hall responses. The spin-flip component of the coupling induces an inverse -wave spin texture in the altermagnetic bands, signaling the onset of an altermagnetic topological phase. This coupling also renders the Rashba–Edelstein effect strongly in-plane anisotropic, enhancing the transverse response relative to ferromagnetic or antiferromagnetic analogues. These results establish interfacial spin-flip tunneling as a practical control knob for direction-sensitive, stray-field–free spin–charge conversion in correlated topological heterostructures.
{"title":"Interface controlled Berry phase and anisotropic spin–charge conversion in altermagnet–topological insulator bilayers","authors":"Juhi Singh, Narayan Mohanta","doi":"10.1016/j.mtquan.2025.100058","DOIUrl":"10.1016/j.mtquan.2025.100058","url":null,"abstract":"<div><div>We propose an altermagnet–topological insulator bilayer as a platform to engineer Berry phase driven spin–charge responses using an interfacial buffer layer. Using a momentum-space lattice model and linear-response theory, we investigate a <span><math><mi>d</mi></math></span>-wave altermagnet coupled to a topological insulator and highlight the crucial role of spin-flip tunneling in shaping its electronic and transport properties. Interfacial hybridization strongly modifies the band structure, leading to anisotropic Rashba–Edelstein and Hall responses. The spin-flip component of the coupling induces an inverse <span><math><mi>d</mi></math></span>-wave spin texture in the altermagnetic bands, signaling the onset of an altermagnetic topological phase. This coupling also renders the Rashba–Edelstein effect strongly in-plane anisotropic, enhancing the transverse response relative to ferromagnetic or antiferromagnetic analogues. These results establish interfacial spin-flip tunneling as a practical control knob for direction-sensitive, stray-field–free spin–charge conversion in correlated topological heterostructures.</div></div>","PeriodicalId":100894,"journal":{"name":"Materials Today Quantum","volume":"8 ","pages":"Article 100058"},"PeriodicalIF":0.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145684135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01Epub Date: 2025-10-16DOI: 10.1016/j.mtquan.2025.100056
Houhao Wang , Sergey Y. Savrasov , Xiangang Wan , Feng Tang
Topological band crossings (BCs) such as Dirac and Weyl points can provide intriguing physical properties in both fermionic systems and bosonic systems, like surface Fermi arcs, chiral anomaly, spin-momentum locking, and among others. Unlike BCs at high-symmetry points (HSPs) formed by a single degenerate irreducible representation (irrep), those in high-symmetry lines (HSLs) are degeneracies formed by two different irreps. For fermionic systems, such BCs near the Fermi level can be effectively diagnosed using symmetry data at HSPs, namely, the number of times each irrep of occupied bands occurs at HSPs. For phonon systems, phonon BCs in the entire frequency window are meaningful. Here, we propose a new diagnostic scheme for detecting phonon BCs by compatibility relations (CRs), which would otherwise be invisible to traditional methods as applied in electronic bands. Based on 230 space groups, we apply our diagnostic scheme to the Phonon Database at Kyoto University (consisting of 10,034 materials) and identify 2,815,357 emergent particles (EMPs) in HSLs. These EMPs include C-1 WP, C-2 DP, C-2 WP, C-3 WP, DP, P-WNL, P-WNLs, QDP, QTP, and TP, providing a platform to assist experimentalists in exploring the practical application value of phonon EMPs. Our diagnostic scheme can also be applied to other bosonic systems like photon and magnon systems and extended to other symmetries, such as magnetic space groups and spin space groups.
{"title":"Diagnosis of enforced phonon band crossings in the entire frequency window by compatibility relations","authors":"Houhao Wang , Sergey Y. Savrasov , Xiangang Wan , Feng Tang","doi":"10.1016/j.mtquan.2025.100056","DOIUrl":"10.1016/j.mtquan.2025.100056","url":null,"abstract":"<div><div>Topological band crossings (BCs) such as Dirac and Weyl points can provide intriguing physical properties in both fermionic systems and bosonic systems, like surface Fermi arcs, chiral anomaly, spin-momentum locking, and among others. Unlike BCs at high-symmetry points (HSPs) formed by a single degenerate irreducible representation (irrep), those in high-symmetry lines (HSLs) are degeneracies formed by two different irreps. For fermionic systems, such BCs near the Fermi level can be effectively diagnosed using symmetry data at HSPs, namely, the number of times each irrep of occupied bands occurs at HSPs. For phonon systems, phonon BCs in the entire frequency window are meaningful. Here, we propose a new diagnostic scheme for detecting phonon BCs by compatibility relations (CRs), which would otherwise be invisible to traditional methods as applied in electronic bands. Based on 230 space groups, we apply our diagnostic scheme to the Phonon Database at Kyoto University (consisting of 10,034 materials) and identify 2,815,357 emergent particles (EMPs) in HSLs. These EMPs include C-1 WP, C-2 DP, C-2 WP, C-3 WP, DP, P-WNL, P-WNLs, QDP, QTP, and TP, providing a platform to assist experimentalists in exploring the practical application value of phonon EMPs. Our diagnostic scheme can also be applied to other bosonic systems like photon and magnon systems and extended to other symmetries, such as magnetic space groups and spin space groups.</div></div>","PeriodicalId":100894,"journal":{"name":"Materials Today Quantum","volume":"8 ","pages":"Article 100056"},"PeriodicalIF":0.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145364168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01Epub Date: 2025-09-11DOI: 10.1016/j.mtquan.2025.100052
Debasis Dutta , Raihan Ahammed , Yingdong Wei , Xiaokai Pan , Xiaoshuang Chen , Lin Wang , Amit Agarwal
Detecting topological phase transitions in bulk is challenging due to the limitations of surface-sensitive probes like ARPES. Here, we demonstrate that nonlinear bulk photocurrents, specifically shift and injection currents, serve as effective probes of topological transitions in noncentrosymmetric materials. These photocurrents show a robust polarity reversal across the phase transition, offering a direct optical signature that distinguishes strong topological phases from weak or trivial ones. This effect originates from a reorganization of key band geometric quantities, the Berry curvature and shift vector, on time-reversal-invariant momentum planes. Using a low-energy Dirac model, we trace this behavior to a band inversion in the time-reversal-invariant momentum plane that drives the topological transition. We validate these findings through tight-binding model for BiTe and first-principles calculations for ZrTe and BiTeI, where the topological phase can be tuned by pressure or temperature. Our results establish nonlinear photocurrent as a sensitive and broadly applicable alternative probe of topological phase transitions.
{"title":"Nonlinear bulk photocurrent probe Z2 topological phase transition in noncentrosymmetric materials","authors":"Debasis Dutta , Raihan Ahammed , Yingdong Wei , Xiaokai Pan , Xiaoshuang Chen , Lin Wang , Amit Agarwal","doi":"10.1016/j.mtquan.2025.100052","DOIUrl":"10.1016/j.mtquan.2025.100052","url":null,"abstract":"<div><div>Detecting topological phase transitions in bulk is challenging due to the limitations of surface-sensitive probes like ARPES. Here, we demonstrate that nonlinear bulk photocurrents, specifically shift and injection currents, serve as effective probes of <span><math><msub><mrow><mi>Z</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> topological transitions in noncentrosymmetric materials. These photocurrents show a robust polarity reversal across the <span><math><msub><mrow><mi>Z</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> phase transition, offering a direct optical signature that distinguishes strong topological phases from weak or trivial ones. This effect originates from a reorganization of key band geometric quantities, the Berry curvature and shift vector, on time-reversal-invariant momentum planes. Using a low-energy Dirac model, we trace this behavior to a band inversion in the time-reversal-invariant momentum plane that drives the topological transition. We validate these findings through tight-binding model for Bi<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>Te<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> and first-principles calculations for ZrTe<span><math><msub><mrow></mrow><mrow><mn>5</mn></mrow></msub></math></span> and BiTeI, where the topological phase can be tuned by pressure or temperature. Our results establish nonlinear photocurrent as a sensitive and broadly applicable alternative probe of <span><math><msub><mrow><mi>Z</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> topological phase transitions.</div></div>","PeriodicalId":100894,"journal":{"name":"Materials Today Quantum","volume":"8 ","pages":"Article 100052"},"PeriodicalIF":0.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145098463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01Epub Date: 2025-09-25DOI: 10.1016/j.mtquan.2025.100055
Chen Zhang , Shengyuan A. Yang , Y.X. Zhao
Quantum states naturally represent symmetry groups, though often in a projective sense. Intriguingly, the projective nature of crystalline symmetries has remained underexplored until very recently. A series of groundbreaking theoretical and experimental studies have now brought this to light, demonstrating that projective representations of crystal symmetries lead to remarkable consequences in condensed matter physics and various artificial crystals, particularly in their connection to topological phenomena. In this article, we explain the basic ideas and notions underpinning these recent developments and share our perspective on this emerging research area. We specifically highlight that the appearance of momentum-space nonsymmorphic symmetry is a unique feature of projective crystal symmetry representations. This, in turn, has the profound consequence of reducing the fundamental domain of momentum space to all possible flat compact manifolds, which include torus and Klein bottle in 2D and the ten platycosms in 3D, presenting a significantly richer landscape for topological structures than conventional settings. Finally, the ongoing efforts and promising future research directions are discussed.
{"title":"Projective crystal symmetry and topological phases","authors":"Chen Zhang , Shengyuan A. Yang , Y.X. Zhao","doi":"10.1016/j.mtquan.2025.100055","DOIUrl":"10.1016/j.mtquan.2025.100055","url":null,"abstract":"<div><div>Quantum states naturally represent symmetry groups, though often in a projective sense. Intriguingly, the projective nature of crystalline symmetries has remained underexplored until very recently. A series of groundbreaking theoretical and experimental studies have now brought this to light, demonstrating that projective representations of crystal symmetries lead to remarkable consequences in condensed matter physics and various artificial crystals, particularly in their connection to topological phenomena. In this article, we explain the basic ideas and notions underpinning these recent developments and share our perspective on this emerging research area. We specifically highlight that the appearance of momentum-space nonsymmorphic symmetry is a unique feature of projective crystal symmetry representations. This, in turn, has the profound consequence of reducing the fundamental domain of momentum space to all possible flat compact manifolds, which include torus and Klein bottle in 2D and the ten platycosms in 3D, presenting a significantly richer landscape for topological structures than conventional settings. Finally, the ongoing efforts and promising future research directions are discussed.</div></div>","PeriodicalId":100894,"journal":{"name":"Materials Today Quantum","volume":"8 ","pages":"Article 100055"},"PeriodicalIF":0.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145159187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01Epub Date: 2025-10-23DOI: 10.1016/j.mtquan.2025.100057
Po-Yao Chang
Topological nodal-line semimetals (NLSMs) are a new family of topological materials characterized by electronic band crossings that form lines in the Brillouin zone. These NLSMs host exotic nodal-line structures and exhibit distinct features such as drumhead surface states and unique electromagnetic responses. This review classifies various NLSM types based on their nodal structures and protecting symmetries, highlighting that these nodal-line structures can form links, knots, and chains. We discuss their characteristic electromagnetic responses, including Landau level spectroscopy, optical conductivity, and permittivity. Furthermore, the strong correlation effects in these NLSMs modify their semimetallic phases and lead to novel quantum phases where magnetism and superconductivity intertwine.
{"title":"Nodal-line semimetals and their variance","authors":"Po-Yao Chang","doi":"10.1016/j.mtquan.2025.100057","DOIUrl":"10.1016/j.mtquan.2025.100057","url":null,"abstract":"<div><div>Topological nodal-line semimetals (NLSMs) are a new family of topological materials characterized by electronic band crossings that form lines in the Brillouin zone. These NLSMs host exotic nodal-line structures and exhibit distinct features such as drumhead surface states and unique electromagnetic responses. This review classifies various NLSM types based on their nodal structures and protecting symmetries, highlighting that these nodal-line structures can form links, knots, and chains. We discuss their characteristic electromagnetic responses, including Landau level spectroscopy, optical conductivity, and permittivity. Furthermore, the strong correlation effects in these NLSMs modify their semimetallic phases and lead to novel quantum phases where magnetism and superconductivity intertwine.</div></div>","PeriodicalId":100894,"journal":{"name":"Materials Today Quantum","volume":"8 ","pages":"Article 100057"},"PeriodicalIF":0.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145364167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Three-dimensional topological semimetals hosting Dirac or Weyl fermions are a new kind of materials class in which conduction and valence bands cross each other. Such materials harbor a nontrivial Berry phase, which is an additional geometrical phase factor arising along the path of an adiabatic surface and can give rise to experimentally measurable quantities such as an anomalous Hall component. Here we report a systematic study of quantum oscillations of thermoelectric power in single crystals of the topological Dirac nodal-line semimetal BaAl4. We show that the thermoelectric power (TEP) is a sensitive probe of the multiple oscillation frequencies in this material, with two of these frequencies shown to originate from the three-dimensional Dirac band. The detected Berry phase provides evidence of the angular dependence and non-trivial state under high magnetic fields. We also have probed the signatures of Zeeman splitting, from which we have extracted the Landé -factor for this system, providing further insight into the non-trivial topology of this family of materials.
{"title":"Thermoelectric quantum oscillations and Zeeman splitting in topological Dirac semimetal BaAl4","authors":"P.R. Mandal , Kefeng Wang , Tarapada Sarkar , Prathum Saraf , Danila Sokratov , Johnpierre Paglione","doi":"10.1016/j.mtquan.2025.100054","DOIUrl":"10.1016/j.mtquan.2025.100054","url":null,"abstract":"<div><div>Three-dimensional topological semimetals hosting Dirac or Weyl fermions are a new kind of materials class in which conduction and valence bands cross each other. Such materials harbor a nontrivial Berry phase, which is an additional geometrical phase factor arising along the path of an adiabatic surface and can give rise to experimentally measurable quantities such as an anomalous Hall component. Here we report a systematic study of quantum oscillations of thermoelectric power in single crystals of the topological Dirac nodal-line semimetal BaAl<sub>4</sub>. We show that the thermoelectric power (TEP) is a sensitive probe of the multiple oscillation frequencies in this material, with two of these frequencies shown to originate from the three-dimensional Dirac band. The detected Berry phase provides evidence of the angular dependence and non-trivial state under high magnetic fields. We also have probed the signatures of Zeeman splitting, from which we have extracted the Landé <span><math><mi>g</mi></math></span>-factor for this system, providing further insight into the non-trivial topology of this family of materials.</div></div>","PeriodicalId":100894,"journal":{"name":"Materials Today Quantum","volume":"8 ","pages":"Article 100054"},"PeriodicalIF":0.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145159185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-01Epub Date: 2025-06-18DOI: 10.1016/j.mtquan.2025.100045
Lingyu Yang , Gia-Wei Chern , Shi-Zeng Lin
We propose a protocol to realize synthetic superconductors in one-dimensional topological systems that host Majorana fermions. By periodically driving a localized Majorana mode across the system, our protocol realizes a topological pumping of Majorana fermions, analogous to the adiabatic Thouless pumping of electrical charges. Importantly, similar to the realization of a Chern insulator through Thouless pumping, we show that pumping of Majorana zero modes could lead to a superconductor in the two dimensions of space and synthetic time. The Floquet theory is employed to map the driven one-dimensional system to a two-dimensional synthetic system by considering frequency as a new dimension. We demonstrate such Floquet superconductors using the Kitaev -wave superconductor chain, a prototypical 1D topological system, as well as its more realistic realization in the 1D Kondo lattice model as examples. We further show the appearance of Majorana mode at the Floquet zone boundary in an intermediate drive frequency region. Our work suggests a driven magnetic spiral coupled to a superconductor as a promising platform for the realization of novel topological superconductors.
{"title":"Driven Majorana modes: A route to synthetic px+ipy superconductivity","authors":"Lingyu Yang , Gia-Wei Chern , Shi-Zeng Lin","doi":"10.1016/j.mtquan.2025.100045","DOIUrl":"10.1016/j.mtquan.2025.100045","url":null,"abstract":"<div><div>We propose a protocol to realize synthetic <span><math><mrow><msub><mrow><mi>p</mi></mrow><mrow><mi>x</mi></mrow></msub><mo>+</mo><mi>i</mi><msub><mrow><mi>p</mi></mrow><mrow><mi>y</mi></mrow></msub></mrow></math></span> superconductors in one-dimensional topological systems that host Majorana fermions. By periodically driving a localized Majorana mode across the system, our protocol realizes a topological pumping of Majorana fermions, analogous to the adiabatic Thouless pumping of electrical charges. Importantly, similar to the realization of a Chern insulator through Thouless pumping, we show that pumping of Majorana zero modes could lead to a <span><math><mrow><msub><mrow><mi>p</mi></mrow><mrow><mi>x</mi></mrow></msub><mo>+</mo><mi>i</mi><msub><mrow><mi>p</mi></mrow><mrow><mi>y</mi></mrow></msub></mrow></math></span> superconductor in the two dimensions of space and synthetic time. The Floquet theory is employed to map the driven one-dimensional system to a two-dimensional synthetic system by considering frequency as a new dimension. We demonstrate such Floquet <span><math><mrow><msub><mrow><mi>p</mi></mrow><mrow><mi>x</mi></mrow></msub><mo>+</mo><mi>i</mi><msub><mrow><mi>p</mi></mrow><mrow><mi>y</mi></mrow></msub></mrow></math></span> superconductors using the Kitaev <span><math><mi>p</mi></math></span>-wave superconductor chain, a prototypical 1D topological system, as well as its more realistic realization in the 1D Kondo lattice model as examples. We further show the appearance of Majorana <span><math><mi>π</mi></math></span> mode at the Floquet zone boundary in an intermediate drive frequency region. Our work suggests a driven magnetic spiral coupled to a superconductor as a promising platform for the realization of novel topological superconductors.</div></div>","PeriodicalId":100894,"journal":{"name":"Materials Today Quantum","volume":"7 ","pages":"Article 100045"},"PeriodicalIF":0.0,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144365926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-01Epub Date: 2025-08-10DOI: 10.1016/j.mtquan.2025.100049
M. Cristina Rodríguez , Analia Zwick , Gonzalo A. Álvarez
Quantum probes offer a powerful platform for exploring environmental dynamics, particularly through their sensitivity to decoherence processes. In this work, we investigate the emergence of critical behavior in the estimation of the environmental memory time , modeled as an Ornstein–Uhlenbeck process characterized by a Lorentzian spectral density. Using dynamically controlled qubit-based sensors—realized experimentally via solid-state Nuclear Magnetic Resonance (NMR) and supported by numerical simulations—we implement tailored filter functions to interrogate the environmental noise spectrum and extract from its spectral width. Our results reveal a sharp transition in estimation performance between short-memory (SM) and long-memory (LM) regimes, reflected in a non-monotonic estimation error that resembles a phase transition. This behavior is accompanied by an avoided-crossing-like structure in the estimated parameter space, indicative of two competing solutions near the critical point. These features underscore the interplay between control, decoherence, and inference in open quantum systems. Beyond their fundamental significance, these critical phenomena offer a practical diagnostic tool for identifying dynamical regimes and optimizing quantum sensing protocols. By exploiting this criticality, our findings pave the way for adaptive control strategies aimed at enhancing precision in quantum parameter estimation—particularly in complex or structured environments such as spin networks, diffusive media, and quantum materials.
{"title":"Manifestation of critical effects in environmental parameter estimation using a quantum sensor under dynamical control","authors":"M. Cristina Rodríguez , Analia Zwick , Gonzalo A. Álvarez","doi":"10.1016/j.mtquan.2025.100049","DOIUrl":"10.1016/j.mtquan.2025.100049","url":null,"abstract":"<div><div>Quantum probes offer a powerful platform for exploring environmental dynamics, particularly through their sensitivity to decoherence processes. In this work, we investigate the emergence of critical behavior in the estimation of the environmental memory time <span><math><msub><mrow><mi>τ</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span>, modeled as an Ornstein–Uhlenbeck process characterized by a Lorentzian spectral density. Using dynamically controlled qubit-based sensors—realized experimentally via solid-state Nuclear Magnetic Resonance (NMR) and supported by numerical simulations—we implement tailored filter functions to interrogate the environmental noise spectrum and extract <span><math><msub><mrow><mi>τ</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span> from its spectral width. Our results reveal a sharp transition in estimation performance between short-memory (SM) and long-memory (LM) regimes, reflected in a non-monotonic estimation error that resembles a phase transition. This behavior is accompanied by an avoided-crossing-like structure in the estimated parameter space, indicative of two competing solutions near the critical point. These features underscore the interplay between control, decoherence, and inference in open quantum systems. Beyond their fundamental significance, these critical phenomena offer a practical diagnostic tool for identifying dynamical regimes and optimizing quantum sensing protocols. By exploiting this criticality, our findings pave the way for adaptive control strategies aimed at enhancing precision in quantum parameter estimation—particularly in complex or structured environments such as spin networks, diffusive media, and quantum materials.</div></div>","PeriodicalId":100894,"journal":{"name":"Materials Today Quantum","volume":"7 ","pages":"Article 100049"},"PeriodicalIF":0.0,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144831158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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