Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:2511.03412 · Science Advances

Quantum-elevated Chiral Discrimination for Bio-molecules

Yiquan Yang, Xiaolong Hu, Wei Du, Shuhe Wu, Peiyu Yang, Guzhi Bao, Weiping Zhang

quant-phSubmitted Nov 5, 2025• Announced Nov 6, 2025• 1 citation
v1 · Nov 5, 2025v2 · Nov 11, 2025
arXivHTMLPDF

Abstract

Chiral discrimination of enantiomeric biomolecules is vital in chemistry, biology, and medicine. Conventional methods, relying on circularly polarized light, face weak chiroptical signals and potential photodamage. Despite extensive efforts to improve sensitivity under low-photon exposure, classical chiral probes remain fundamentally bounded by the shot-noise limit due to quantum fluctuations. To beat these limitations, we demonstrate quantum-elevated chiral discrimination using continuous-variable polarization-entangled states as moderate-photon-flux, high-sensitivity, quantum-noise-squeezed chiral probes. We achieve a 5 dB improvement beyond the SNL in distinguishing L- and D-amino acids in liquid phase. This non-destructive, biocompatible protocol enables high-sensitivity chiral analysis, with broad implications for drug development, biochemical research, environmental monitoring, and asymmetric synthesis.

Journal reference
Sci. Adv.12,eaea8201(2026)
DOI
10.1126/sciadv.aea8201

Related papers

Quantum-enhanced estimation of stimulated Raman optical activity

Mahadeva Chanda Durjoy, Girish S. Agarwal

In recent times there has been growing interest in Raman optical activity (ROA) for its label free detection of absolute configuration, conformation, and stereochemical structure in chiral biosamples and drug molecules. Since ROA signals are generally small, techniques such as stimulation by a probe beam can be used to enhance the signal strength. However, with a classical probe, the measurement precision is still fundamentally limited by its shot noise. To solve this problem we propose the use of two-mode squeezed vacuum and show that it can achieve sub-shot noise limited measurement sensitivity. Using quantum estimation theory, we derived the quantum Fisher information and the quantum Cramér-Rao bound (QCRB) for stimulated ROA measurement to quantify the precision enhancement. This improvement comes from photon-number correlations which suppress the intensity fluctuation common to both modes. We further show that balanced detection of the output intensity difference is a practical measurement scheme that approaches the QCRB and becomes optimal in the small-chirality limit. This opens a promising path toward more sensitive Raman chiroptical spectroscopy of weak and photosensitive samples.

quant-pharXiv:2606.23722•Physical Review A•Jun 22, 2026•0 citations

Sub-shot-Noise Circular Dichroism Spectroscopy for the Accelerated Characterization of Molecular Chirality

Korenobu Matsuzaki, Tahei Tahara

Circular dichroism (CD), which detects differential absorption with left- and right-circularly polarized light, is widely used for characterizing molecular chirality. Despite its similarity to absorption spectroscopy, CD spectroscopy typically requires a significantly longer time to acquire a spectrum due to the low intensity of the CD signal. The CD measurements can be accelerated if the noise level in the spectra can be reduced, which facilitates the detection of the weak CD signal. Here we show that such noise suppression is indeed possible using entangled photon pairs as the light source. By taking advantage of the photon number correlation of entangled photon pairs, we suppressed the noise contained in the CD spectra by 30% below the shot-noise limit which is a fundamental limit in conventional CD measurements. As a consequence, sub-shot-noise CD spectroscopy developed in this study is capable of characterizing the molecular chirality twice as fast as conventional CD spectroscopy.

ACS Photonics•Apr 2, 2024•4 citations

Quantum limits to chiroptical molecular discrimination

Mikael P. Backlund

Discriminating enantiomer pairs is of central importance in the molecular sciences. The preferential interaction between chiral light and matter is commonly employed in this discrimination, despite fundamental challenges. Here we present quantitative error bounds for classifying the handedness of a chiral, randomly oriented, quantum optical emitter from the perspective of classical and quantum hypothesis testing. Most interestingly, we find that a collective measurement on $N$ photons can provide an orders-of-magnitude improvement in error rate relative to a corresponding separable measurement.

quant-pharXiv:2607.19136•Jul 22, 2026•0 citations

Quantum optical rotatory dispersion

Nora Tischler, Mario Krenn, Robert Fickler +3 more

The phenomenon of molecular optical activity manifests itself as the rotation of the plane of linear polarization when light passes through chiral media. Measurements of optical activity and its wavelength dependence, that is, optical rotatory dispersion, can reveal information about intricate properties of molecules, such as the three-dimensional arrangement of atoms comprising a molecule. Given a limited probe power, quantum metrology offers the possibility of outperforming classical measurements. This has particular appeal when samples may be damaged by high power, which is a potential concern for chiroptical studies. We present the first experiment in which multiwavelength polarization-entangled photon pairs are used to measure the optical activity and optical rotatory dispersion exhibited by a solution of chiral molecules. Our work paves the way for quantum-enhanced measurements of chirality, with potential applications in chemistry, biology, materials science, and the pharmaceutical industry. The scheme that we use for probing wavelength dependence not only allows one to surpass the information extracted per photon in a classical measurement but also can be used for more general differential measurements.

arXiv:1701.00944•Science Advances•Oct 6, 2016•43 citations

Quantum Fisher information bounds on precision limits of circular dichroism

Jiaxuan Wang, G. S. Agarwal

Circular dichroism is a widely used technique for investigating optically chiral molecules, especially for biomolecules. It is thus of great importance that these parameters be estimated precisely so that the molecules with desired functionalities can be designed. In order to surpass the limits of classical measurements, we need to probe the system with quantum light. We develop the quantum Fisher information matrix (QFIM) for precision estimates of the circular dichroism and the optical rotary dispersion for a variety of input quantum states of light that are easily accessible in the laboratory. The Cramer-Rao bounds for all four chirality parameters are obtained from the QFIM for (a) single photon input states with a specific linear polarization and for (b) NOON states having two photons with both either left polarized or right polarized. The QFIM bounds, using quantum light, are compared with bounds obtained for classical light beams, i.e., beams in coherent states. Quite generally, both the single-photon state and the NOON state exhibit superior precision in the estimation of absorption and phase shift in relation to a coherent source of comparable intensity, especially in the weak-absorption regime. In particular, the NOON state naturally offers the best precision among the three. We compare QFIM bounds with the error sensitivity bounds, as the latter are relatively easier to measure whereas the QFIM bounds require full state tomography.

arXiv:2108.13970•Physical Review A•Dec 16, 2021•10 citations

Quantum sensing of biomolecules: principles, progress, and prospects

Sourav Mishra, Craig McBeth, Oluwasesan Adegoke +2 more

Abstract Quantum sensing (QS) is a rapidly developing field at the intersection of physics, biology, and nanotechnology. It holds great promise for improving how we detect biomolecules in health, diagnostics, and environmental monitoring, and this potential is reflected in the rapid development and growing interest in advanced biosensing technologies. Traditional sensing methods, while useful, often face limits in sensitivity, speed, and the ability to analyze tiny amounts or subtle changes in biomolecules. QS uses coherence, entanglement, and superposition to achieve much higher sensitivity and precision than classical techniques. These technologies rely on advanced platforms like nitrogen-vacancy centers in diamonds, quantum dots. They can measure tiny changes in magnetic fields, electric charges, or fluorescence signals caused by biomolecules like proteins, DNA, lipids, carbohydrates and metabolites. This review explains the fundamental principles behind QS and explores how various physical platforms are used to detect and study biomolecules. It highlights recent breakthroughs in detecting single molecules, monitoring enzymatic reactions in real time, and imaging biological structures with quantum-level detail. We also discuss how nanotechnology is powering the field, improving integration through nanoparticle coupling, microfluidics, and specialized bio interfaces to target and amplify signals in practical settings. This review discusses current efforts to overcome existing challenges and highlights future directions, including the development of quantum-enhanced clinical sensors, integration with artificial intelligence for data analysis, and hybrid quantum–classical sensing strategies. These advances are expected to accelerate the translation of quantum biosensing technologies from laboratory demonstrations to practical clinical and environmental applications in the coming decade.

Journal of Physics Photonics•Jun 1, 2026•1 citation
Chiral discrimination of enantiomeric biomolecules is vital in chemistry, biology, and medicine. Conventional methods, relying on circularly polarized light, face weak chiroptical signals and potential photodamage. Despite extensive efforts to improve sensitivity under low-photon exposure, classical chiral probes remain fundamentally bounded by the shot-noise limit due to quantum fluctuations. To beat these limitations, we demonstrate quantum-elevated chiral discrimination using continuous-variable polarization-entangled states as moderate-photon-flux, high-sensitivity, quantum-noise-squeezed chiral probes. We achieve a 5 dB improvement beyond the SNL in distinguishing L- and D-amino acids in liquid phase. This non-destructive, biocompatible protocol enables high-sensitivity chiral analysis, with broad implications for drug development, biochemical research, environmental monitoring, and asymmetric synthesis.
In recent times there has been growing interest in Raman optical activity (ROA) for its label free detection of absolute configuration, conformation, and stereochemical structure in chiral biosamples and drug molecules. Since ROA signals are generally small, techniques such as stimulation by a probe beam can be used to enhance the signal strength. However, with a classical probe, the measurement precision is still fundamentally limited by its shot noise. To solve this problem we propose the use of two-mode squeezed vacuum and show that it can achieve sub-shot noise limited measurement sensitivity. Using quantum estimation theory, we derived the quantum Fisher information and the quantum Cramér-Rao bound (QCRB) for stimulated ROA measurement to quantify the precision enhancement. This improvement comes from photon-number correlations which suppress the intensity fluctuation common to both modes. We further show that balanced detection of the output intensity difference is a practical measurement scheme that approaches the QCRB and becomes optimal in the small-chirality limit. This opens a promising path toward more sensitive Raman chiroptical spectroscopy of weak and photosensitive samples.
Circular dichroism (CD), which detects differential absorption with left- and right-circularly polarized light, is widely used for characterizing molecular chirality. Despite its similarity to absorption spectroscopy, CD spectroscopy typically requires a significantly longer time to acquire a spectrum due to the low intensity of the CD signal. The CD measurements can be accelerated if the noise level in the spectra can be reduced, which facilitates the detection of the weak CD signal. Here we show that such noise suppression is indeed possible using entangled photon pairs as the light source. By taking advantage of the photon number correlation of entangled photon pairs, we suppressed the noise contained in the CD spectra by 30% below the shot-noise limit which is a fundamental limit in conventional CD measurements. As a consequence, sub-shot-noise CD spectroscopy developed in this study is capable of characterizing the molecular chirality twice as fast as conventional CD spectroscopy.
Discriminating enantiomer pairs is of central importance in the molecular sciences. The preferential interaction between chiral light and matter is commonly employed in this discrimination, despite fundamental challenges. Here we present quantitative error bounds for classifying the handedness of a chiral, randomly oriented, quantum optical emitter from the perspective of classical and quantum hypothesis testing. Most interestingly, we find that a collective measurement on NNN photons can provide an orders-of-magnitude improvement in error rate relative to a corresponding separable measurement.
The phenomenon of molecular optical activity manifests itself as the rotation of the plane of linear polarization when light passes through chiral media. Measurements of optical activity and its wavelength dependence, that is, optical rotatory dispersion, can reveal information about intricate properties of molecules, such as the three-dimensional arrangement of atoms comprising a molecule. Given a limited probe power, quantum metrology offers the possibility of outperforming classical measurements. This has particular appeal when samples may be damaged by high power, which is a potential concern for chiroptical studies. We present the first experiment in which multiwavelength polarization-entangled photon pairs are used to measure the optical activity and optical rotatory dispersion exhibited by a solution of chiral molecules. Our work paves the way for quantum-enhanced measurements of chirality, with potential applications in chemistry, biology, materials science, and the pharmaceutical industry. The scheme that we use for probing wavelength dependence not only allows one to surpass the information extracted per photon in a classical measurement but also can be used for more general differential measurements.
Circular dichroism is a widely used technique for investigating optically chiral molecules, especially for biomolecules. It is thus of great importance that these parameters be estimated precisely so that the molecules with desired functionalities can be designed. In order to surpass the limits of classical measurements, we need to probe the system with quantum light. We develop the quantum Fisher information matrix (QFIM) for precision estimates of the circular dichroism and the optical rotary dispersion for a variety of input quantum states of light that are easily accessible in the laboratory. The Cramer-Rao bounds for all four chirality parameters are obtained from the QFIM for (a) single photon input states with a specific linear polarization and for (b) NOON states having two photons with both either left polarized or right polarized. The QFIM bounds, using quantum light, are compared with bounds obtained for classical light beams, i.e., beams in coherent states. Quite generally, both the single-photon state and the NOON state exhibit superior precision in the estimation of absorption and phase shift in relation to a coherent source of comparable intensity, especially in the weak-absorption regime. In particular, the NOON state naturally offers the best precision among the three. We compare QFIM bounds with the error sensitivity bounds, as the latter are relatively easier to measure whereas the QFIM bounds require full state tomography.
Abstract Quantum sensing (QS) is a rapidly developing field at the intersection of physics, biology, and nanotechnology. It holds great promise for improving how we detect biomolecules in health, diagnostics, and environmental monitoring, and this potential is reflected in the rapid development and growing interest in advanced biosensing technologies. Traditional sensing methods, while useful, often face limits in sensitivity, speed, and the ability to analyze tiny amounts or subtle changes in biomolecules. QS uses coherence, entanglement, and superposition to achieve much higher sensitivity and precision than classical techniques. These technologies rely on advanced platforms like nitrogen-vacancy centers in diamonds, quantum dots. They can measure tiny changes in magnetic fields, electric charges, or fluorescence signals caused by biomolecules like proteins, DNA, lipids, carbohydrates and metabolites. This review explains the fundamental principles behind QS and explores how various physical platforms are used to detect and study biomolecules. It highlights recent breakthroughs in detecting single molecules, monitoring enzymatic reactions in real time, and imaging biological structures with quantum-level detail. We also discuss how nanotechnology is powering the field, improving integration through nanoparticle coupling, microfluidics, and specialized bio interfaces to target and amplify signals in practical settings. This review discusses current efforts to overcome existing challenges and highlights future directions, including the development of quantum-enhanced clinical sensors, integration with artificial intelligence for data analysis, and hybrid quantum–classical sensing strategies. These advances are expected to accelerate the translation of quantum biosensing technologies from laboratory demonstrations to practical clinical and environmental applications in the coming decade.